Early ... Intro Picture

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Alberte and Bernard Pullman

          Pullma A + B 1977 Alberte Pullman (nee Bucher) was born in 1920.

Interview with Mme Prof. Dr. Alberte Pullman

Paris, Institut de Biologie-Chimique, October 28, 1997, 11:00.

Mme Dr. Alberte Pullman: In your writing on the story of quantum chemistry, you start with what?

Dr. Anders: With Hückel.

P: Not before? Not Heitler and London?

A: It will depend to some extent on how the writing develops - I could indeed refer to this to some extent. As things stand I will start with Hückel, followed by certain applications, whereby I will naturally make good use of the books written by you and your late husband. (1-3). But then something on the later semiempirical methods as well. And in your case something also on Otto Schmidt (5-9), Dr. Otto Schmidt - -

P: Yes, yes - I know what you mean - -

A: By the way, two years after your citations of Schmidt in your papers, he died in 1943 (4).

P: I knew he had died. But I didn't know when exactly - he died so early?

A: Well, he lived from 1874-1943. Some more questions. Mme Prof. Pullman when are you born?

P: In 1920.

A: Lacassagne mentions - in the book of your husband and you, of 1955, Cancérisation par les substances chimiques et structure moléculaire - that you were a mathematician by training (2; 6)?

P: Well - this is a bit exaggerated. In those times the scientific studies in France were as follows: normally you started with a licence, this was normally three years of studies. One year was chemistry (general chemistry), the other one was general physics and the third one was more mathematical. The order was indifferent. And it was going to become compulsory to have, as a preliminary, general mathematics. In my time you could still be going directly to mécanique rationelle - classical mechanics - or calculus. Either one. When I finished, general mathematics would become compulsory. But by choice I did it. So - in a way people can say I am a chemist, I'm a physicist or I'm a mathematician. But I wouldn't dare saying I am a mathematician in front of any mathematician!

The other reason is that during the war, or just before - I started in 1938/39 - I worked to make a living in order to go through my studies. For that reason I worked at the Institut Poincaré, the red building just next door, which was an institute for mathematics. In there, the CNRS (Centre National de la Recherche Scientifique) had a center for calculations. By hand, with logarithms, slide rule and mechanical calculator machines. We had to do all kinds of calculations: in the first year these were calculations of trajectories of projectiles. Then the direction was changed to another area and we made calculations for all kinds of people who needed things like statistics etc. So, since I had worked there for a few years while finishing my license, people had a tendency to tell that I was a mathematician. But that was not mathematics, I was doing calculations - that was all. When I finished my license I had some experience with practical mathematical calculations and how to do these things.

A: And you then worked with Daudel. Is it true how Lacassagne describes it (2; 6), how he came in contact with Daudel?

P: Yes, it's very simple. There was the Institut du Radium which is next door to us {Institut de Biologie Physico-Chimique, Interviewer's note, I.'s n.}, just across the courtyard. This Institute was the real building of Mme Curie (who had died in 1934). In 1943 it was directed by Mme Joliot. The Institut du Radium had one building and a little courtyard and across the courtyard was the Pavillon Pasteur of the Institut du Radium, which had been founded after what Mme Curie had done during the First World War for the health of soldiers etc. This was just across the courtyard and its director was professor Lacassagne. Daudel was, at that time, assistant to Mme Joliot at the Institut du Radium. Being just 20 meters across, Daudel and Lacassagne were talking to each other frequently. The person who saw the first paper by Otto Schmidt was Lacassagne. And what he said in the preface to our book (2; 1-8) is perfectly true. The 'cancer people' were all very aware of everything that was published in their field concerning the possible reasons of carcinogenicity for various compounds. So when looking through the literature he saw the summary, I suppose. He didn't read German - or did he read German? At any rate, he couldn't understand the contents since that was not of his speciality. But he was struck by Otto Schmidt's hypothesis that electrons had something to do with the carcinogenicity.

And then, as stated before, he had been acquainted with Daudel. So Lacassagne thought that maybe Daudel, who was half physicist and half chemist, and who was interested in all those things, could tell him whether these hypotheses had any basis in quantum mechanics and whether it might be interesting to pursue. So that's how he talked to Daudel - it's true, it's exactly like he said in his preface.

Daudel looked into it and since he was busy with other things and couldn't do it himself, he told Lacassagne that it was indeed interesting but that the method used by Otto Schmidt seemed very primitive and there were other possibilities of using other methododologies, more refined, based on quantum mechanics. But these had to be studied first and elaborated to be applied to hydrocarbons. He couldn't do it himself but if Lacassagne could provide someone who could do the work, that would perhaps be feasible. Lacassagne was very influential and very well introduced in many organizations where he could get grants. So he got a grant. And on the grant he got me. Since I was experienced in computations, they thought it would be nice. I was not yet specialized in quantum mechanics. I did specialize at that time.

A: Your first paper was on PCl5 (10)?

P: Oh, yes, that was a special thing. That was the first, yes, under my maiden name {Alberte Bucher; I.'s n.}. It came from a question by a chemist to Daudel. Because Lacassagne had no space in his institute - but across the yard there were very few people (it was the war, a lot of people were away), and there were rooms. So Mme Joliot said: "Yes, you can use a room if you wish, you can work here". That's how I started in the Institut du Radium proper.

A: That chemist with the PCl5 question - was that Haïssinski (11)?

P: No, no - wait a minute - - it was Moureu! I think we even mention him in the first note. He put the question, and Daudel gave it to me.

A: Now - your thesis was in 1946. What was your second topic?

P: Réactions d'échange, in chemistry. To be exact: Les réactions d'échange et la nature de la liaison chimique. The second thesis was not an original research, it was a literature search; one had three weeks to do that, one had to dig into all the papers that had been published on the subject. And then to try and make something which made sense, to organize the thing. It was not published in general, it was exposed after the thesis when you defended your thesis, after the main subject.

A: Your thesis, was it on mesomerism?

P: To be exact it was mesomerism as methodology. Here it is. It was a long title, that was fashionable.

Contribution à l'étude de la structure électronique des molécules organiques. Étude particulière des hydrocarbures cancérigènes (12).

You want me to make a photocopy of it? It might be interesting for you that I make a photocopy of the first two pages (I). It is an introduction that situates the problem at the time when I took it.

A: Then you and your husband also published with Rumpf - -

P: Rumpf, Paul Rumpf (13), yes. He was a chemist.

A: Was he important?

P: He was a chemist who could do a lot of chemistry. I published with him too, and my husband also (14).

A: Was he powerful?

P: He was not very powerful, he was a good chemist, and he was at the CNRS. People at the CNRS at the time were not very powerful. The important people were the professors, at the universities. There were people at the CNRS who were directing laboratories and this was the case of Rumpf. He was Maître de Recherche at the time - already a position. He was very modest, also he didn't brag what he did. He was well known in France as a chemist. And he was rather open to you on all things. Which was not the case of every chemist at the time.

A: What about Buu-Hoï (15) {pronounced Bü-oy; I.'s n.} with whom you also published in those days?

P: Buu-Hoï! This was the chemist who made the compounds in Lacassagne's group. Because not only did they try known compounds in painting them on mice, but they also synthesized new compounds to try. Buu-Hoï was the big chief of the synthesis of compounds. And since he was in Lacassagne's group he was open for anything which could help to understand better the results.

So he was the synthetic chemist. If he had been alone I don't know if he would have been so open. You know, quantum chemistry didn't exist at that time. There was the Nature of the Chemical Bond (16) and Heitler and London (17) {with their calculation; I.'s n.} on the hydrogen molecule. They were the first, really, to apply quantum mechanics to the study of the chemical bond in the very simple molecule hydrogen. This was known but not understood by people who were not quantum mechanically inclined.

There were very few people in France who were aware that quantum mechanics could do anything for chemistry. And there was at that time even some resistance by the experimental chemists. So it's quite nice that Paul Rumpf was asking questions and was ready to publish the answers. One of the funny ways of quantum chemistry.

A: The Institut de Biologie Physico-Chimique was a foundation of Baron de Rothschild (18a-c). Later his name appeared again in monetary contributions towards the Jerusalem Symposia (19). Was it because of his scientific interest or because of the cancer problem?

P: It was not because of the cancer problem. Well, let's put it properly. This Institute {Institut de Biologie Physico-Chimique; I.'s n.} was founded by the grandfather of the present Baron Edmond de Rothschild (18a-c). The grandfather was also called Edmond de Rothschild, and he was very generous in general. He gave a lot of money to many things. But as his grandson uses to say, and I've heard him to say that a few times. "My grandfather could be generous because he had no income tax".

Anyhow, between 1920 and 1930, about 1927, he was convinced by his friend Claude Bernard, the big medical person, that he should give something to science and give them {the scientists; I.'s n.} money to build an institute, create an original institute. Claude Bernard suggested that his own friend Jean Perrin, who was a physical chemist and Nobel Prize winner could be the director of the new institute which would be an Institut de Biologie Physico-Chimique and encompass all the applications of physics and chemistry to biological problems. That's why the name is so long. So that was done. The Institute was built with a private foundation, completely private, nothing from the CNRS, which didn't even exist as yet, nothing from the universities. Except of the lent ground on which the Institute was built. That was the foundation of this Institute.

So it did exist when I started at the Institut du Radium. But we didn't work there, we didn't even dream of working there at that time when we started. But they had a magnificent library. And, being on the campus, we were entitled to come and work in the library and consult the journals. And yet another occurrence: one of the known chemists who was working here, Jacques Duclaux, not the communist leader but a scientist, a good physical chemist, was going to the library in his own institute very often and he noticed my husband who was there also very often. My husband was very noticeable because he was bald very early. So he was remarked and later, much later on, it was in 1958, the Institute here asked my husband to come and install a department of Theoretical Biology. That was how we came to this Institute. But this was much later.

We were both at the Institut du Radium until 1954. In 1946 I finished my thesis, my husband had come back from the war in '45, we married. He succeeded me in the grant, that was very funny: There was a good combination because the grant was still valid, but I wanted to enter the CNRS to have a permanent position. A grant covers generally not more than two years. And since I wanted to really do science all the time, I entered the CNRS. Therefore I went to Lacassagne and told him: "You are looking for someone to replace me in the grant; would you take my husband?" He did take my husband! So we worked there until 1954.








Then there was no space at the Institut du Radium any more because it got reorganized, among other things. Theoretical Chemistry had to move and Daudel went to another place. We had more or less separated, by that time we didn't work with Daudel any more. My husband didn't work with anybody particularly, at any time. But it was allright. We had our own group and people already working for us. So we went to a very old building in the rue d'Ulm which belonged to the Institut Curie and which served as an apartment house for some nurses! It's a hilarious story: the nurses found that it was too old and crumbling and not comfortable enough. They wanted something else and they got something else. So the building, which was a very small house, was for nothing and for nobody. The Institut Curie proposed to let us have an apartment downstairs in this building for our lab!

We remained until 1958 when there was the official translation to here, the reason being that they wanted my husband to be the director of a department - a new department which was to be founded in this Institute. The Institute was built in such a way: it had departments of pure biochemistry, applications of physical methods to biochemistry, essentially spectroscopy, various spectroscopies, a few other things, like pure chemistry of biological compounds, already chemistry of the nucleic acids - the beginning of the big department of nucleic acids headed by Michelson. He was an Englishman who came especially to found this department. And each department was independent. They were all independent from each other. There was no central direction which would say: "You do this and then this and I give you that amount of money". It was built in a very particular way for a French institution at that time. It didn't exist elsewhere.

A: Is it still maintained by Baron de Rothschild?

P: It was a foundation and, as said before, the baron was very generous, especially in the beginning. Paid were the current costs, the maintenance of the building etc. But the personnel was paid from other sources. There were some technicians belonging to the Institute who were also paid by the foundation. But the chefs de service were either paid by the CNRS, which meant that they had already a position at the CNRS, or by the universities. And the money to make their department function they had to get from various other sources. So there was no internal competition whatsoever for money, which created a very particular atmosphere, a very nice one. Which is very different from the organization of the CNRS, very, very different! In the CNRS there is a director, who is supposed to direct research, and distribute the money and you have to manage, a situation which never existed in this Institute. But it will now, now it's transformed, unfortunately - - the world is changing.

A: Daudel was director of a CNRS laboratory (20). I explicitly asked him whether I can mention that in my opinion he had very good connections to the ministries and the bureaucracy - -

P: Oh, yes! It is true, it's publicly known. You need connections - - where don't you need connections?

A: Another, rather stupid, question, But I will ask it nevertheless. How many papers do you have?

P: Together? We always worked together, ma husband and I, and we never conceived to work separately on different things. So we made from the beginning a list of our publications together. It's about 850, roughly. My husband has more if you count separately the publications where only my husband is mentioned. He has a few more than I do.

A: Your husband wrote very long papers (21) - and so many - -

P: Yes, he wrote very easily and very well at the same time. He had a gift, obviously, he was well trained in school, and he knew how to make his gift become better and better. So that was precious, very precious.

A: How did you divide up the students? For instance, how did you and your husband decide with whom Berthier would work?

P: He was the first - did he tell you (22)?

A: No - - he didn't explicitly mention that he was the first.

P: Berthier was the first of what we can call our students. We are not like the Americans. In France, maybe you know that we never talk about 'our students', in general. We talk about 'our collaborators'. Which is much nicer. And it was this kind of atmosphere at that time, things were small, and, in a way, closer. He was our first collaborator. 50 years ago - wait a minute - in '47, yes, he started in 1947. He told you (22)?

A: Yes, and he had his first paper in 1948 (23).

P: Exactly. So he started working with us, in '47, at the Institut du Radium, still. He was really with the two of us, at that time we worked together all the time. My husband was finishing his own thesis at the time which was partly theoretical, partly experimental, in the chemistry of radioactive elements, with Haïssinski. But for the theory we were working together all the time.

A: Then there was Mme Serre - -

P: That was later on. We were still at the Institut du Radium, yes, in a different room. There was Berthier, then there came Mme Serre and, practically at the same time, A. Julg.

A: Mme Serre came in 1949?

P: No, no, later on - you found a paper with Mme Serre? She published it with me, I think. Not even Berthier at that time. Mme Serre and me, in 1953, on acetylenic compounds, application of molecular orbitals (24a). And with Julg there was also a paper in 1953 (25), I think his third paper. He published also with my husband (26). Because it was already necessary to divide a little bit.

A: How did you divide it?

P: Just like that - we didn't divide formally. It so happened. You know, we were always in the same room. Berthier, Mme Serre, Julg who was somewhat handicapped since he has had polio when he was 16. Yet he still walked, he came from the ENS {École Normale Supérieure; I.'s n.} which is not far from the Institut du Radium but it was in the same room; we were working and discussing in the same room. With my husband and me we were five in the same room, about this size {about 4 by 7 meters, I.'s n.}.

A: That is small - -

P: Well, the desks were less big and there were only little calculators, electromechanical machines, so that didn't take much space.

A: And the famous Peerless (27).

P: Oh yes, the Peerless - and there were the Friden (28) already, that was the luxury. I started my - - that might be interesting for you: When I started my computations for my thesis I have been using the "mill". I don't remember the trade mark. You remember, the ones with the handle. They were efficient ones once you got used to them, and again, I had experience from the Institut Poincaré calculations. And there was nothing else at that time.

A: Daudel had mentioned that there was a lot of turning in a simple calculation (19) - -

P: Of course - -

A: Then there was Veillard?

P: Yes, but that was quite later on. With the first block there was also Mlle Jeanne Pontis. Yes, wait a minute, when did she come? - -. Oh, yes, she had studied mathematics, she was a little more of a mathematician by formation, she liked it. And she wanted to do research in this kind of field. She came also to the Institut du Radium even before Mme Serre and Julg. But she published perhaps not very quickly (29). She became my husband's assistant at the university later on, but that was much later on, about 1956. She had joined us in the early '50's. So that was the sixth in the room. We were six people to the room!

A: At one point there was a joint publication by you, your husband, together with Berthier, Coulson, and H.H. Greenwood (30).

P: Yes. That was the turning point of the methodology we used. Because first we had used the mesomerism, Slater, Pauling and so on. And we realized that it was becoming impossible to deal with it on a large scale because you had to write all these structures. And since we were not interested in small compounds but in huge compounds, it was too much. It was not very practical to use, although it was powerful. And there were the parallel developments by Longuet-Higgins (31), Coulson (32) in England, all the methodology of Lennard-Jones (33) on the basis of the Hückel method, the method that was called at that time the method of molecular orbitals. We knew Coulson personally - since we had been invited to lecture in England in '47 already. So we had talked and we had contacts and Coulson was interested. He found the story of the carcinogenicity very intriguing and we decided to try to recalculate one of the 4-membered polycyclic hydrocarbons, the naphthacene molecule, by the method of molecular orbitals, which was very simple at that time. It was one of the first publications of Berthier, I think - yes. Berthier, Coulson, myself and my husband. And Greenwood, who was Coulson's assistant and who was doing the calculations of Coulson, the practical work. Coulson was a big professor and he didn't do the practical calculations himself . We published these notes in Comptes Rendus, in French, in France! It was quite an achievement that Coulson consented doing that. Coulson was British, very British, incredibly British!

A: H.H. Greenwood, that's interesting - -

P: What happened to him? Do you know that?

A: Greenwood came out in 1972 with a book (34) containing quite a few quantum chemistry programs, SCF, CI programs, which are still widely copied today. In the sense that new books in quantum chemistry, which even appear only lately - e.g. Rogers (35) - still copy the Greenwood's old programs - although, in this case Rogers does give credit to Greenwood. Later on Greenwood worked in some computing center in England in 1972 (34). There also were some later publications onbiological problems (36a-b). I had hoped that maybe you could give me a hint - -

P: He must be retired by now. Because after all it's 50 years ago these days. He must have been at least 25 when he was working there.

A: Some other question. Why did Longuet-Higgins leave the field of quantum chemistry?

P: I knew - but one forgets the details. He went to America - now he's back to England, he is in Sussex - - He is retired by now. He became interested in the brain and in the origin of life and things like that. So he went to a big institute in California, San Diego, where Crick also went later on, Orgel also (37) and others. There was a time, now I don't know, when they had positions easily available for foreigners or some important people who wanted to come.

A: Kutzelnigg (38) also said that Longuet-Higgins was back in Sussex but that he wouldn't know whether Longuet-Higgins would be willing to answer questions. This afternoon I'm going to meet Prof. Salem - -

P: Oh, he is very knowledgeable about Longuet-Higgins (39).

A: He had one paper with him in 1959 (40). But he himself seems to be adverse talking about his semiempirical days. Why would that be? Many people, for instance Kutzelnigg (40), - they don't want to talk too much about their Hückel days - -

P: No. Kutzelnigg spent one year here -

A: Two years - -

P: Or two years. And it's very funny because he never wanted to do anything with the semiempirical method at a time when everything was full with the applications of the Hückel methodology to biochemical calculations. We were starting the whole thing, it's very funny. And later on he became a very deep theoretician and interested in developing methods and do things very, very accurate (41). That was a new Kutzelnigg for me. I knew him first when he came - from Theo Förster, he was working with Theo Förster (42)- to work with us on applications of the method of molecular orbitals to biological compounds. The only way at that time to do anything was to use the Hückel method. And he didn't even look interested. Nevermind - he spent two years, did a few things, relatively little (43,44). And then went back and we didn't see him for a long time. And we discovered later on that he was becoming a very, very theoretical man and doing very good theory. That was obviously to his taste; he had a different concept. He's quite good.

A: But for teaching purposes his semiempirical display of the Hückel method is at its best (45,46). But for him to remember is another story. There is that discrepancy - - . And Salem wants to talk about reaction surfaces (47) - but not so much about his first book on molecular orbital theory (48). But I will find out the specifics when I meet him this afternoon.

P: Because he thinks ahead of time. Perhaps he thinks one should not go back to the past. You know, some people are like that - -

A: Pople is another one who doesn't want to be brought in connection with his earlier achievements - - with his old CNDO methods (49). At one place - it escapes me where, it must have been in the 80's, he said something like: I know of the deficiencies of the NDO-methods, I developed one (50) - -

P: Nearly every quantum chemistry method is poor when it's new. Then the development starts, of course. What you say about Pople surprises me. For I heard him say one day that when one has a problem what one should do is to use the methodology which is available at the time the problem is raised, knowing all the drawbacks. So maybe he had enough of CNDO and - -

A: That was also something against Dewar - -

P: Of course, the old competition - MINDO etc. (51) - -. Of course it has bad things but it allowed lots of progress.

A: What happened to Monsieur Astic after the computers arrived (52)?

P: Ah, Monsieur Astic - - he had a big crisis. He was our calculator. He was very perturbed. Because, in a way, he didn't like new things in any direction. So he had always a time of adaptation to new things. And there he did not take the train at the right moment. He should have immediately gone. But the way it was done was such that only the research people in the laboratory went to training. That is, the good ones who were more theoretically inclined than others, they were going into the computers. So Astic was a little left behind. Nobody thought of Astic and probably he was lost and he was a little bit shy to learn how to do it. But he had a big shock. So that was really shocking his habits and changing everything. Then he came to it later on - it was really a big difficulty for him. It was a pity because he could have been very helpful, but - - . And there were new technicians, which were appointed for the computer, a programmer, and an operator, and a woman who was punching the cards. So Astic - he learned to punch the cards. But he could do much more, I'm sure. But he remained to do all kinds of things, errands, various services. He remained here, at the end of this corridor, until 1995, when he retired. He was given the retirement pension at the CNRS. I remember my husband was already not very well, but he managed to come for the day. We had a little reception with wine and cookies and he did a little speech for us, and Astic was pleased, one could see that. I have pictures but they are at home - -

A: Speaking of pictures: there once was a meeting at Menton, and there is a picture in a book by your husband and Daudel. I forgot it, but I might send it to you so that you may identify the people on the picture?

P: OK (53).

A: In his book L'Empire des molécules (54; p.109) Daudel claims that you discovered the free valence index. You yourself (2; p.74) gave the credit partly to Svartholm who had developed some ideas within the concept of mesomerism (55), which you then developed further. Daudel picks up that point and he likes to write that you found it. But later on you seem to have given the credit more to Coulson.

P: Because there are two definitions. There is one definition within the mesomerism which we coined l'indice de valence libre and one definition which was by Coulson, essentially, in the method of molecular orbitals, which he named free valence index (56).

A: But Daudel also likes to give that to you - -

P: Oh - he's very kind! Well, I worked a lot at the beginning in this topic, within mesomerism. There was the war - during the German occupation we were in the occupied territory and cut off from everything. We had no communication - neither with America nor with England. So everything we knew were Hückel's papers for the method of molecular orbitals (57), because these were published in the thirties, some also published in 1941 - these were from Germany. There was no difficulty to get these papers - we had the Zeitschrift für Elektrochemie and the other ones in the Institut du Radium, fortunately. But all the publications by Coulson, Longuet-Higgins came later, some of them in '39, and in these years we were not aware of them. We discovered the whole method of molecular orbital development by Coulson and others after the end of the war, after 1945. So we discovered that the indice de valence libre that we had named like that, was also existing in those methods. Perhaps I jumped a little overboard to give more credit to Coulson because - - - nevermind what the origins are.

A: Then there was Clar working also on polycyclic aromatic hydrocarbons (58) - -

P: On spectroscopy - yes. Erich Clar.

A: In England, Manchester - -

P: Already, yes? I even translated one of his papers. You know, Daudel didn't understand a word of German, so it was a full mystery to him what was in Otto Schmidt's papers. But I have seen that the other day - Clar - Schmidt - -. By the way, {while looking at the bookshelf; I.'s n.} - Clar's book has disappeared! Yes, we had this book! And that was very, very useful. But it is a long time ago. Must have been lent to someone who did not returne it. Just one second {searching through some old notes; I.'s n.}. In one of these translations next to it I must have one more. These are Hückel's papers, translated. And here: Erich Clar - Berlin, Springer Verlag, 1941. Aromatische Kohlenwasserstoffe. Yes, I extracted a part of it - yeah, it is funny - -

A: When you were working on the cancer problem, you didn't cite Clar too often, and Clar didn't mention the Pullmans too much. You didn't feel that in that time - -

P: Excluded? No! You know, somebody has committed a book on the cancer problem which is a pure scandal. I forgot his name! You see I have no bad feelings because I even forgot his name. I saw the book recently - putting things in order in my bookshelf and then I discovered this book on the development of the story of the hydrocarbons. Where he puts everything wrong and with a little bit of - - something against us. I don't know why. But this happens - -

A: Was that Zander, a German book (59)?

P: No, it was an American, I think, - - a cancerologist. Oh, it would come back, maybe. This happens.

A: Zander - in some sense a student of Clar's - in his book doesn't cite the Pullmans too much either.

P: You know, I don't think we ever met him {Clar; I.'s n.}. Perhaps not. At least I don't remember - it is so far away. Perhaps, you know, you make yourself an impression of somebody's doing and writing, perhaps we didn't quote him the way he wants to be quoted - who knows. But we were always aware of Clar's work and admiring Clar's work. So there were no bad feelings, at least not from us.

A: Then in your own work you concentrated more and more on the active regions - -

P: This was in my thesis already. This was the beginning.

A: And then in your book, I think in 1963 (3;288): Wasn't always the question of how and why the aromatic hydrocarbons did interact with the proteins, the nucleic acids? Later Daudel mentions the epoxide formation (60) - - -

P: No, it's more complicated than that. The K-region, - the theory about the carcinogenic compounds, was in my thesis. I have first found the K-region, essentially, which was on the side of the molecule (2). Then later on there was the development with more calculations. And we added another region, which was the L-region (61), and another proposition to the theory which said that the K-region was the one by which the carcinogenic compound would interact with something in the cell - - at the beginning there was no precision - something in the cell, provided it didn't have an L-region. It would be too reactive and involve the molecule in other processes.

A: I always admire the way you put this exactly in this sense (2; 288). If one reads it nowadays it strikes one as having been written very carefully - -

P: Oh, yes, it had to be written carefully - -

A: It was precisely that, looking back at it, from a later point of view, that it appeared clear that the K-regions must interact somehow and - the writing is beautifully, written very tentatively. I somehow admire the way it's done - -

P: It had to be carefully written because these were bold hypotheses. Later on we added the M-region (M for metabolism) but very little was known at the time. Concerning the K-region I was very conforted with - that may be interesting for you - -. I was very conforted, very early, by an experiment by Heidelberger (62) who found, from an experiment in biochemistry - - who found that obviously there were addition compounds between the K-regions and proteins: he found products of reactions with proteins. Thus at that time everybody believed, lots of people, I must say, believed that this was the thing which started cancer. Much later on it appeared likely that it was not so: To promote cancer was not an addition on the K-region but a - - how can one say it - - a secondary reaction, a metabolisation followed by an attack by an epoxide on nucleic acid, not on the proteins. Although we had touched the problem of metabolism in the early theory, the state of knowledge 50 years ago was not sufficient to reach such a conclusion.

It remains of the theory that the K-region is really a very reactive region in these hydrocarbons, a feature confirmed (after the theory) by lots of chemical experiments, and that the K-L-theory allowed a surprisingly good classification of the carcinogens and the non-carcinogens. Nowadays a unified theory of the mechanism of action is actively searched by numerous people. The bonding to the nucleic acids through a metabolite has opened new vistas.

A: And it is the reason why you entered the nucleic acids proper?

P: Oh no, no, no. This is much before. It happened that in the fifties - in the second part of the fifties! The theory of the carcinogens being at that time at the top of its success, we were asked to turn towards chemotherapeutic agents.

The people who were dealing with chemotherapy were aware of the developments in carcinogenesis. So they came to us and asked us if we would try and deal with a series of agents which were known as useful in chemotherapy, look at the electronic structure and try to find something in common. So this led to nucleic acid compounds quite naturally, since most of the chemotherapeutic agents were either purines or pyrimidines or analogues, that is substituted purines and pyrimidines. Thus we started to deal with these molecules. Not in view of dealing with the nucleic acids! Remember that was in the middle fifties! Watson and Crick were at the point of coming out (63). We didn't know much, nobody knew much. But we comuted the chemotherapeutic agents. These led us naturally, immediately - when Watson and Crick's structure of nucleic acids, appeared - to deal with the bases themselves. The ones which were in the nucleic acids, and then we started working a lot on the nucleic acids. This was the origin - the chemotherapy.

A: Was the chemotherapeutical interest medical, industrial or academic among the cancerologists?

P: These were medical people - Jean Bernard. He was a specialist in blood, leukemia and things like that. He was a big, big, big professor at the center of medicine at l'hôpital St. Louis in Paris. He is still alive, very old, retired. Anyway, he had read our papers, he had known what it was about and he came to us because he was interested in practical chemotherapy, with patients. They used these compounds.

A: Your husband - he came from Poland,, to France, then went to England, to Africa during the war - where did he learn his quantum chemistry from?

P: In France when he came back in '45.

A: Not during - -

P: No, he had no time. During the war, he was all over Africa. And well, as he used to say when he was in a good mood - he was always in a good mood, - - when he was in the mood of telling war stories. He said "Yes, I liberated Erythrea, Lybia and Syria."

A: But he immediately started to work in science when he returned?

P: Oh, yes, we were married three weeks after he came back - we were engaged since '39. You know in theses times, you got engaged. So we got married three weeks after, he was still an officer here in the army. And he came to work with me immediately after being discharged.

A: He immediately had papers out - I wondered about that.

P: Because he always wanted to do science, even when he was, I don't know, 13, 15, he was interested. We met at the Sorbonne in the first year of our studies, in chemistry. And we had always decided to work together. I also wanted to do that. So we decided that we would work together, to do science together. And it so happened that I started here in '43 when he was doing all these things I didn't know about. Again, we were not in contact. So I had paved the way, in a way. He could immediately get a grant. But he says in his reminiscences - well, the story went like that:

Löwdin was nice enough when my husband turned 60 to make a symposium for his 60th birthday. But he called it very nicely; he said: "He is 60, she looks 40" - which is not true of course - "so we are going to call it the Pullman centennial". We had a symposium and at this symposium my husband was asked to give a paper on his reminiscences (64). In this paper he tells how he came to quantum chemistry and said: "I became a quantum chemist not by choice but by marriage" It was so funny - -

A: I think I will make my description of quantum chemistry by countries. Because in that period, as you said before, things developed, due to the separation, differently according to the distances - -

P: Of course. The developments in America were different. There was a big contribution by Mulliken, which we were not really aware of. Oh, well, perhaps I heard him mentioned. You know, between Pauling and Mulliken there was always a kind of antagonism. Mulliken is very little quoted in Slater and Pauling.

So I got acquainted with Mulliken essentially after the war. We had a very important symposium in Paris in 1948 to which came all the big shots: Pauling, Mulliken, Coulson - all the big shots in quantum chemistry. We were still at the Institut du Radium. And there we really learned what the developments had been everywhere in the meantime. That was very interesting. We knew already the names, but the details - we started to read them in '45, '46. You know the book by Pauling, The Nature of the Chemical Bond which had appeared just before the war (65). It was not translated, it was in English. A big book like that we didn't know. We got a microfilm, I don't know by what channels. We had it on microfilm - that's the way I read Pauling's book. Daudel didn't mention it? He has forgotten! I was the one who read most of it at the time. Oh, I can show it to you, I think I have it - if I didn't misplace it, which is the worst you can do {searching for it. I.'s n.}. Here it is: Pauling's book, a tiny roll only, but we had a machine to read it. Here - check, it's really Pauling's book! It's in a good state.

A: Yes, indeed I can recognize the title page.

P: We have the book now, of course. Later on we bought it. I forgot through which channels we got it {the microfilm; I.'s n.}, it was completely clandestine, through the provinces: at first the German occupation was only in the north. So it would go through the south, something like that could filter - -

And here in the same drawer is something you might find interesting: All the mesomeric formulae of naphthacene. They are all here. I had a very large table - probably as big as this one {about 2 x 1 meters, I.'s n.}. I calculated with them all the elements of the matrix by superposition. But you had to have all of them on the table to do that. I remember that Mme Joliot who was the director of the Institut had the terrible habit of entering without knocking. And I was always scared that, when I had the window open, she would come in vividly and it would all blow away.

A: Professor Julg showed me something similar - a page of paper, 1 by 2 meters, where he had assembled over 4000 elements of the azulene matrix (26) - -

P: Of course, we had to do calculations but you had to see the matrix before you to get everything done. We had the things on transparent paper which was very scarce. {Looking at the box containing the paper clips containing the mesomeric formulas; I.'s n.} All that in an English box of tea which I think my husband brought back in 1945 when he came back from his long stay in the English Army.

A: When are you going to write your autobiography?

P: Well, in principle not my autobiography, but I have been asked to try and write a history of the Pullman lab. But that's terrible work! I'm trying to do it. You can't just tell little stories, it has to be scientific - -. And it is a lot of work. I am not a hundred percent sure I will succeed.

A: But it would be very important piece of history - not only of quantum chemistry in general but also of French quantum chemistry. Because Paris was a center. I asked Berthier why he had gone to the Pullmans' and Berthier had answered that Bernard Pullman had convinced him (22). With Kutzelnigg it was the same story, he had listened to a talk of your husband at Freiburg (40). So the French did have a huge influence in central Europe and for that reason a book from a historic point of view - -

P: Well, I'm trying. I am not ready. It's going to be a lot of work. And I'm not that young after all.

A: But you look young - -

P: You're very kind.- I feel young - -

A: But you can say that Anders wrote such a bad book - -. And you certainly can give a much better story - -. You see, I think Dewar's autobiography (66) is a very informative to know, to have Mulliken's which is also very interesting (67) - -

P: All autobiographies in general are worth reading. One learns a lot of this. Did you read McWeeny's papers on his scientific life (68)? He did work in the Hückel method. But he is more of a theoretician. But it's very well done - and very well written!

A: McWeeny had once encouraged me when he said that it would be interesting if something were written about the Hückel story - - . McWeeny had used Gaussian functions before Boys (70) - - McWeeny also had some Hückel papers out - I copied some - . So your husband did also publish about chaos theory (71)?

P: No, not chaos, I show you the book {getting the book from the bookshelf; I.'s n.}. When he retired from the university which was when he was 68 (it was a few years ago - about 1987) he was still chef de service in this Institute (The chefs de service were elected until they were 70. And some even could be prolonged). He had become director of the Institute many years ago. (Incidentally it is a good point for Quantum Chemistry: this biochemical, biophysical Institute was purely experimental, before us. We came and started a department of theoretical biochemistry, and after a few years, when they had to replace the Director of the whole Institute, they asked my husband - a theoretician! Is that not interesting? I'm not bragging about this. But I think it's a good point: it means that they were interested.)

So when he retired - and then retired also from his department here - he remained Director of the Institute because they couldn't find a replacement. He remained quite a while. But he had more time. He decided that he would not like to do research again and again and again and bore the young people. He would do something else which he liked, which he had always liked. That was the product: L'Atome dans l'histoire de la pensée humaine, from the Greeks to nowadays (72). So that's that book which appeared in 1995.

A: Is that book still in print? Would I find it at the Presses Universitaires?

P: No, no. The Presses Universitaires {the publishing house; I.'s n.} have his tiny, little book, popular science. The "Atom" was at Fayard - they are specialized. They are very good at history and things like that. So it's really the history of the notion of atom from the Greeks, Demokrit, Thales etc., until now - the concept of the atom. All the discussions throughout the centuries. And the fights against the atomic theory, Middle Ages, the Church, lots of people, Auguste Comte later on, all these people who were against the atomic theory. The atoms couldn't be seen - and so on and so forth. And it lasted a long time. The book goes until the latest developments.

A: Coming back to your person for some more questions. You had started with Daudel and then studied all the compounds, you began to study all kinds of physical properties. You always used the newest methods - Hückel, NDO, Gaussians (73) - -. Behind this: what was your theme? Was the theme to know more about the compounds, did the research carry you away or what was in the back of your mind when you used all the different methods? Did you want to learn more about the molecules?

P: Yes, essentially! Structure and function! Structure: why it functions like that, where do the properties come from, and so on. For all the molecules. At the beginning it was more organic chemistry, big molecules, not tiny, little ones but large molecules! You might notice that very few people have dealt with large molecules by the Hückel methodology. We really were the ones who realized what could be done. You know, chemists learned the properties of their molecules by experiments. But these were the manifestations of the properties. We wanted to know what was behind this behavior. Chemists, physicists (essentially; at the beginning it were the spectroscopists) were seeing that all kinds of effects happened. - all kinds of effects which, by calculating these molecules, were explained or even discovered. Lots of properties were predicted - by the Hückel method applied in a proper way - -

A: So it was a chemical theme you had in the back of your mind?

P: Yes. At the beginning it was chemistry, organic chemistry - you have seen our book - the first one ?

A: 1952.

P: Electronic theory (1) - this was the beginning of the spreading of what we had done. This was - I must admit, that it was my husband's idea to make a book right away with what we had done. And in the first two years there were a lot of things which we calculated. One day he got this idea: Why don't we make a book to explain these things to people. And so we did. You heard of Roald Hoffmann of course, the Nobel prize winner (74)? He told us one day that he had learned all these things in our book, in French. Because he speaks a lot of languages. He is a Jew, he came from Austria as a child through France, he spent a little time in France, then later on went to America. But while he went to school in France, he learned French, and later, when our book appeared he read it in French and he learned all the things in this book. And Salem - I don't know if he tells it to you - -. But he uses to say, generally, that he learned, that he decided, what he wanted to do in life in reading my husband's little que sais-je you mentioned some time ago on the structure.

A: Another question back to Salem. Funny that he doesn't want to talk about semiempirical methods - -

P: Well, probably he thinks it's over - -

A: Of course it's over - But we want to report to - -

P: But he didn't use them very much - -

A: Yes, that's true. But he wrote - -

P: He wrote a very good book, very useful (47,48). He taught it for a while. He had to teach it - he was a professor at Orsay, and he had to teach the methodology of quantum chemistry. So I don't know. I don't see why. Perhaps he has bad memories of his period as a prof? He was a very good teacher, very clear

A: An interesting thought on the side: French quantum books in Germany are very hard to find. Julg's books are not to be located in Germany via Interlibrary Loan. Nothing. Your books - with the exception of the Constance University library - are also fairly rare to find. For instance the book Cancérisation ... - I only got it since Prof. Berthier made me a copy of it.

P: He made a copy? Very kind of him!

A: A very interesting book with many historic details of that period. So there is that language barrier - -

P: Perhaps some comes from the old antagonism. Not now. But you know, our book appeared not so far from the war. There was still some feelings maybe, and the language barrier - well, of course, probably. There are very few French people who know German, and it's reciprocal. I don't know, because I don't look for them, but maybe it's difficult to find German books in France, who knows? I don't know, I never try it. Because in German - I was quite an exception among young scientists. It so happens that I learned German in school and my father was Swiss, from the German speaking part of Switzerland. So I always had some - he tried to teach me. I am not bilingual, but at least I can pronounce German properly which is very rare in France. It's true. I don't know, I never understood why it was difficult for a Frenchman talking German. It has a lot of logic. And maybe there was very early an antagonism. Now there is none, generally. Well, I was an exception and Daudel was so happy that I could translate - so I translated. I dug them {the translations; I.'s n.} out, just to show them to you - -

Which was difficult at the time because I didn't know much in science at the time. Scientific language is not so easy. And maybe it {the translation; I.'s n.} contains all sorts of mistakes. But it still could be used. Otherwise German is perfectly untransparent if you don't have the slightest idea of the language - you can't get the ideas. In English you may get some things but in German you can't, you have to know the words.

A: Hückel never used his own method; there was only one later paper in 1954 (75), fairly unknown, - also in Zeitschrift für Elektrochemie (of which he was the chief editor). Otherwise - nothing on the use of his method. If you know German then you should read his autobiography (76)!

P: So there is an autobiography? I don't know that - -

A: All German profs seem to dislike it.

P: Why?

A: It's loosely written, in a way like we talk here today. Neither Kutzelnigg nor Heilbronner like it's style. They maintain it's too personal. Hückel seems to have been a rather withdrawn type of person. His autobiography is much more personal than Mulliken's, for instance. Hückel gives many personal thoughts and details on topics of everyday life and brings out his tastes on a row of things - -

P: My husband had in his office a picture of Hückel, for a long time. We got it, I don't know why, from I don't know where. He looks very sympathetic, intelligent. I have it at home. He made big progress with his methodology. And there are important things which developed through the Hückel theory. We did a lot of things - - after all, our book - the last one, on quantum biochemistry - which was written in English, the big one - which was on all the biological compounds, everything containing p -electrons. There are lots of them. This is one thing we discovered in turning to biochemistry: that in biological compounds of living matter there are lots of molecules with p -electrons. You could deal with them at that time with the Hückel method.

All of the early calculations on biological compounds were done by the Hückel methodology. And we found a lot of things which remain valid nowadays, even when you do all kinds of ab initio - with CI and what not - calculations. A lot could be found - provided you had, of course, an idea - I mean, using it in the proper way. Most people were looking for too much precision, and too much accuracy. You know when one big shot, in America, at one of the early congresses in the States in the fifties, said that we should be looking for an accuracy of 1 Kcal/mole - that was stupid at the time because it was impossible. And, if you had it on your mind, you could always criticize all what was done by semiempirical methods: it was not of the accuracy of 1 Kcal/mole. But that's not necessary for most of the things which we drew out of our Hückel calculations. You have to know what is possible to get out of your computers ahead of time. You have to be very conscious of where you can go. And what you can get from your calculations. Very often the evolution of the properties throughout a series of analogous compounds for instance - these can be practically gotten with any method - provided you use it intelligently.

A: For calculations of, for instance, transition states one would need a great precision - -

P: That's something else. This is one reason why I never wanted really to deal with reactivity problems at the accurate level. The way of reaction surfaces and these things, I tried to avoid. It was very fashionable, now it's less. And particularly with enzyme chemistry, I think it's such a danger - you can get anything you want, nearly.

A: And with a surface - when do you know whether you calculated a local or a global extremum - -

P: Well, some people can deal with it, some people are interested, but I am not. Period. And my husband was the same, absolutely the same. He was looking for trends, evolutions of properties, it was one very big thing he was interested in. And all kind of things like that - we found lots of things (19c)! I now remember that I've written once one article, (it was at the time when it became fashionable to despise these semiempirical and Hückel methods) showing that the relative values of the dipole moments of the bases of the nucleic acids and even their directions were very similar when computed by all the methods, up to ab initio. The title of the paper is very typical of may attitude at that time: "The present image of heteroaromatics in quantum chemistry: revolution or evolution?". (19b). Of course, the absolute values were different, but the trends were the same.

A: Some people call Hückel's method 'empirical' - -

P: That was empirical, yes, then came the semiempirical ones with Pariser and Parr and so on. And there came a confusion when people started to do calculations with empirical potential functions. It's a different thing.

A: Are you also working on these modern methods like DFT?

P: We are trying a little bit, with Berthier.

A: Berthier said he doesn't like ab initio and DFT methods - -

P: Well, he is changing his mind a little bit because there are some results which seem to indicate possibilities. But we are not there, yet. It's very fashionable at the moment, very fashionable. I went to Atlanta to the big congress of quantum chemistry this summer in June. At this quantum chemistry meeting, the fashion, really the fashion was the application of DFT. This is really the boom. But in some years it may go down - already in a few years. People are always looking for perfection. And now they realize that perfection is never quite there and you can always put some improvement and another one and another one. Thus you are never there, and you cannot deal with huge systems. So now you go to DFT in the hope that it will short-circuit the problems. Parr is very active in this topic, very much. There are lots of people who are interested.

So - more questions?

A: Yes. Mme Pullman - did you have children?

P: Yes, two. Two boys - -

A: On the side of all - -

P: On the side, yes, because we always led a very active life - -. We were working a lot, we were seeing people a lot, I mean, all the other scientists, foreigners essentially. When they came to France we made it a point to invite them at home. This is not much done in France, you know. Ordinarily one goes to a restaurant, and even that - -. But we always tried to do this also. And we also traveled a lot from very early on.

My oldest son was born exactly four weeks before the opening of the 1948 meeting in Paris. There was a banquet, of course, like always on these meetings. There were very few women at that time in science in France, there were even very few women accompanying their husbands. I was a scientist and I happened to be the only woman at the meeting, aside I believe, from Inga Fischer. I was sitting next to Mulliken - the first time I met him, very impressed, you know: Mulliken! - I was 20-something and was sitting next to Mulliken! But my English was very, very poor at the time. I could read properly, very well, but - - (now I've been to America many times). And the conversation was a little difficult - I don't know if you ever met Mulliken - the American English and Mulliken's English were very difficult - so I had trouble. Anyhow, we tried to lead a conversation and at one time he asked me "Do you have children?" and I said "Yes, I had a baby four weeks ago" - "Ha" he said "- - -" and I understood that he had added that he had a grand daughter just at the same time. So I said: "Oh, you are a grandfather." and he answered "No, I have had a daughter myself." You know, to me he looked like an old man. But we remained very good friends, even though I had made a big mistake.

A: Did Mulliken have a young wife?

P: No, she was not so much younger than he was. But this was a late child. She had problems. I think she committed suicide in the end, very late. She was living with him. She had some kind of a depression, in the last time. I think - doesn't he mention it in his autobiography? Anyhow. I've read about it somewhere. We knew each other very well after such a long time. I remember that his daughter and my son played somewhere on the beach at Cape Cod when they were children.

I had another boy who was born only eight years later, who was very different from the first one. So it was a headache to bring up these kids with all the rest. The older one works in an administration. He studied chemistry for a while, but he found it a bit difficult. You know, it's difficult to have two parents who are in the field, very difficult. He didn't even enter the field really, he studied. But he figured that it was best not to try to enter the field. The second one teaches at the university ethnology and anthropology. The most remote science possible from his parents, I think. That's he who choose it.

A: Now let us think - he was 20 in 1968 {the time of the so-called "student revolt"; I.'s n.}!?

P: The oldest. He was not touched, not much. He was never very interested in politics and things like that. The second one, who was much younger, he was 12, he was in the lycée - he didn't manifest, he didn't participate in the events, but he was strongly influenced for his later life. Perhaps this is one of the sources of his going out of 'our' science - -

A: 1968 was a very strong year in France, in Paris - -

P: Oh, yes! That was a revolution! That was really a revolution in the sense that it changed everything in the way of life. Very strange. The consequences were very strong in France. Because everything opened. I mean lots of things: people worked a lot, they used to be very regular and conservatists. There were leftists, too of course. But nevermind. It opened the gates for a lot of things, everything changed: the way of life, the way the children considered their parents - - well, probably it was too much, too tight before, and it exploded - -

A: One more question: what do you think of the Euro-business.

P: Well, I don't know, I'm not sure - -

A: Do you think it will work?

P: That's the problem - it's on the go, it will happen. But whether it's going to work? That's something else. Well, finances are not my cup of tea.

A: Mme Prof. Pullman, I thank you very much for this interview. More than anybody else so far you have given such a direct and open account of 'old times'. Thank you very much.


References and notes

(1) Alberte Pullman, Bernard Pullman, Les Théories Électroniques de la Chimie Organique.

Masson, Paris, 1952.

(2) Alberte Pullman, Bernard Pullman, Cancérisation par les substances chimiques et

structure moléculaire. Masson, Paris, 1955.

(3) Bernard Pullman, Alberte Pullman,, Quantum Biochemistry.

Interscience, New York, 1963.

(4) Dr. Otto Schmidt (O.S.) was born on Sept. 8, 1874 at Cologne and died May 17, 1943 at Heidelberg, according to the Stadtarchiv of the German town of Heidelberg. Information on his life and industrial work is rather scetchy. The town archive of Ludwigshafen/Rhein - a center of German chemistry during this period - has registered O.S. as living at the address Lisztstraße 113 from 1913-1938, which must be considered the period of his professional life. As can be learned from the references O.S. had worked at the BASF (Badische Anilin- und Sodafabrik) from 1922-1923 (9d) and later on at the Hauptlaboratorium der I.-G. Farbenindustrie A.-G (9a;1862). In reference (9c;356) O.S. thanked a certain coworker Dr. Grosskinsky for his help in the Hauptlaboratorium der IG-Farbenindustrie; O.S. finished this particular paper at the end of 1931 at the California Institute of Pasadena, with special thanks to Linus Pauling. For an industrial chemist such a research stay in the US at that time has to be considered highly exceptional - O.S. must have had quite some weight in the IG-Farbenindustrie. Yet in his later papers, e.g. reference (7), he no longer mentions any working address, although still living at Ludwigshafen. Strangely, an archive search of the present BASF, a successor company of the former IG-Farbenidustrie, could not furnish any results as to personal entries concerning O.S. A search in the Chemical Abstracts (9e) shows several Otto Schmidt in the period 1925-1939, one apparently working in the US pulp industry. Presumably one of the first papers of Dr. Otto Schmidt, Ludwigshafen, is the one of reference (9g). Later, from July 7, 1939 on, O.S. was officially registered as living at Heidelberg-Ziegelhausen, Schönauerstr 16a, from where his last paper (8) is published. The search of the township of Heidelberg did not even yield an announcement of his death in the local newspaper - somewhat amazing since his widow survived him for 19 years and for the same reason likewise surprising, since at the end of reference (6;110), a certain Dipl.-Ing. Heini Schmidt, Stuttgart, is thanked for his help in a publication and further that there also was a joint publication of O.S. and Heini Schmidt, reference (7); the relationship of the latter to O.S. is as yet unclear.

(5) O. Schmidt, Die Beziehung zwischen Dichteverteilung bestimmter Valenzelektronen

(B-Elektronen) und Reaktivität bei aromatischen Kohlenwasserstoffen.

Z. physik. Chemie, 39, 59-82 (1938).

(6) O. Schmidt, Die Charakterisierung der einfachen und Krebs erzeugenden aromati-

schen Kohlenwasserstoffe durch die Dichteverteilung bestimmter Valenz-

elektronen (B-Elektronen). (Zweite Mitteilung über Dichteverteilungen

der B-Elektronen). Z. physik. Chemie, 42, 83-110 (1939).

(7) O. Schmidt, H. Schmidt, Weitere Untersuchungen zum Kastenmodell (Zylinderring, Kom-

pression der B-Elektronen). (Dritte Mitteilung über Dichteverteilung und

Energiespektrum der B-Elektronen). Z. physik. Chemie, 44, 185-202 (1939).

(8) O. Schmidt, Charakterisierung und Mechanismen der Krebs erzeugenden Kohlen-

wasserstoffe. Die Naturwissenschaften, 29, 146-150 (1941).

(9a) O. Schmidt, Die Deutung der Spaltungsregeln. Chem Ber. 69, 1855-1862 (1936).

(9b) O. Schmidt, Beiträge zur Theorie der homoiopolaren Valenz: Die Deutung der

Spaltungsregeln für Olefine und Radikale.

Z. Elektrochem., 42, 175-184 (1936).

(9c) O. Schmidt,Über den Ort der Sprengungen von C–C-Bindungen in Kettenmolekülen.

(4. Mitteilung über Reaktionsmechanismen).

Z. physik. Chemie, A159, 337-356 (1932).

(9d) O. Schmidt, Zur Frage der Anwesenheit von Wasserstoffionen unter den wie üblich

erhaltenen positiven Thermionen. (3. Mitteilung über Hydrierungskatalyse.)

Z. Physik. Chemie, A152, 269-283 (1931).

(9e) Chemical Abstracts, Author Index 1927-1936, page 2436.

(9f) O. Schmidt, Beiträge zur Kenntnis der katalytischen Hydrierung organischer

Substanzen. Z. physik. Chemie, A118, 193-239 (1925).

(9g) H. Scheibler und O. Schmidt, Die Einwirkung von Kohlenoxyd auf Keten- und Ester-

Enolate .... Chem. Ber., 58, 1189-1197 (1925).

(10) R. Daudel, A. Bucher, H. Moureu, Une nouvelle méthode d'étude des valences dirigées.

Son application à la détermination de la structure des penta-

halogénures de phosphore.Comptes Rend. 218, 917-918 (1944).

(11) e.g.: R. Daudel and M. Haissinskï, Oxydo-réduction, transfert d'électrons et valence.

Bull. Soc. Chim. France, 1945, M970-975.

(12a) A.Pullman, Thèse. Masson, Paris, 1946.

(12b) A.Pullman, Influence de l'addition des cycles saturés sur la structure électronique

et sur l'activité cancérigène des hydrocarbures polycycliques.

Comptes Rend. 224, 120-122 (1947).

(13) e.g. P. Rumpf, Forces intermoléculaires et liaison hydrogène.

Bull. Soc. Chim. France, 1948, 211-230.

(14a) A. Pullman, B. Pullman, P. Rumpf, Structure électronique du fulvène et du benzo-

fulvène. I. L'étude par la méthode de la mésomerie.

Bull. Soc. Chim. France 1948, 280-284.

(14) A. Pullman, B. Pullman, P. Rumpf, Structure électronique du fulvène et du benzo-

fulvène. II: Étude par la méthode des orbitales moléculaires.

Bull. Soc. Chim. France 1948, 757-761.

(15) e.g. N.P. Buu-Hoï, Contribution à l'étude des substances antibactériennes de synthèse.

Comptes Rend. 221, 202-204 (1945).

(16) L. Pauling. Nature of the Chemical Bond and the Structure of Molecules and Crystals.

Cornell Univ. Press (3rd) 1960. The first edition came out in 1938.

(17) W. Heitler and F. London, Wechselwirkung neutraler Atome und homöopolare Bindung

nach der Quantenmechanik.

Zeitschr. Physik, 44, 455-472 (1927).

(18a) Some remarks on the Rothschild family:

Moses Amschel (born in Hannover, Germany, in 1734) had opened a shop in Frankfurt/Main, Germany, under the logo of a red shield (German: Das Rot(h)e Schild(t)), where the name is supposed to originate from, at least according to ref. (18b), under a green shield according to ref (18c). His son Mayer Amschel (1743-1812) founded a bank at Kassel, Germany and all his five sons, in their turn, founded new banks in different European countries. One of them, James (Jakob) Mayer Amschel (1792-1868), founded a bank at Paris, always working closely together with his brothers, especially with the one at London. Partly due to this, his bank could make a huge financial success at the Paris stock exchange by the clever use of a slight time advantage in the first few hours following the Battle of Waterloo in 1815. His son Edmond James de Rothschild (1845-1934) was an important contributor towards cultural societies in France as well as to the zionistic movement. He was also the founder of the Institut de Biologie Physico-Chimique. One of his sons was Maurice Edmond Charles de Rothschild (1881-1957), followed by his son Edmond James de Rothschild (1926-1997), who was quoted here. See also ref. 18b-c.

(18b) Anonymus, Enciclopedia Zanichelli. Zanichelli, Bologna, 1994.

(18c) F. Morton, Die Rothschilds. Deutscher Taschenbuch Verlag, München, 1998.

(19a) The Jerusalem Symposia on Quantum Chemistry and Biochemistry.

The first volume was: E.D. Bergman, B. Pullman (Eds.),

I: Physico-Chemical Mechanisms of Carcinogenesis.

Proceedings of an International Symposium held at Jerusalem Oct. 21.-25, 1968.

Israel Acad. of Sciences and Humanities, Jerusalem, 1969.

(19b) A. Pullman, The Present Image of Hetero-Aromatics in Quantum Chemistry -

Revolution or Evolution? in: E.D. Bergman, B. Pullman (Eds.): The

Jerusalem Symposia on Quantum Chemistry and Biochemistry.

II: Quantum Aspects of Hetrocyclic Compounds in Chemistry and

Biochemistry, 2, 9 (1970). Proceedings of an International Symposium held at

Jerusalem March 31.-April 4, 1969.

Israel Acad. of Sciences and Humanities, Jerusalem, 1970.

(19c) e.g.: A. Pullman and B. Pullman, Natural Hypsochromic Shifts.

Disc Farad. Soc. 9, 46-52 (1950).

(20) See: Interview with R. Daudel, Paris, June 3, 1997.

(21) Among the earlier longer papers see e.g.

B. Pullman, Emploi des diagrammes moléculaires dans la cinétique chimique:

représentation de la configuration électronique de l'état de transition.

Bull. Soc. Chim. (France), 1948, M 273.

(22) See: Interview with G. Berthier, Paris, June 2, 1997.

(23a) A. Pullman and G.Berthier, Structure électronique de l'azulène.

Comptes Rend. 227, 677-679 (1948).

(23b) G.Berthier and B. Pullman, Sur la conjugaison simultanée de plusieurs

groupments extracycliques avec un noyau aromatique.

Bull. Soc. Chim. (France), 1948, M 554-558.

(24) J. Serre and A. Pullman, Recherches théorques sur les composés acétyléniques.

I. Structure électronique de l'acétylène.

J. Chim. Phys., 50, 445-458 (1953).

(25) A. Julg and A. Pullman, Structure électronique du fulvène. Introduction de l'interaction

configurationelle. J. Chim. Phys., 50, 459-467 (1953).

(26) See: Interview with A. Julg, Sept. 1997.

(28) For a brief story of the German electromechanical calculating machine Peerless,

see Interview with G. Berthier, Paris, June 2, 1997, ref (7).

(28) The electromechanical calulators Friden, as well as the Marchant machines, were widely

used machines in the fifties and sixties (I.'s n.).

(29a) A. Pullman, B. Pullman, E.D. Bergmann, G. Berthier and J. Pontis, Fulvènes et éthylènes

thermochromes. 10e. Recherches sur les naphtofulvènes.

Bull. Soc Chim. France, 1951, 681-685.

(29b) also e.g.: G. Berthier, B. Pullman and J. Pontis, Recherches théoriques sur les

constantes de force et les fréquences de vibration du

groupement carbonyle dans les molécules organiques

conjugées. J. Chim. Phys., 49, 367-376 (1952).

(29c) also e.g.: , B. Pullman, A. Pullman, G. Berthier and J. Pontis, Les pléiadiènes.

J. Chim. Phys., 49, 20-23 (1952).

(29d) A later publication when J Pontis was married to Baudet (During that time, J. Baudet,

according to A. Pullman, served as a university assitant to B. Pullman):

J. Baudet, G. Berthier and B. Pullman, Sur la fréquence de vibration du groupement

carbonyle dans les quinones polycycliques.

J. Chim. Phys., 54, 282-284 (1957).

(30) G. Berthier, C.A. Coulson, H.H. Greenwood and A. Pullman, Structure électronique des

hydrocarbures aromatiques à 4 noyaux benzèniques accolés. Étude par

la méthode des orbitales moléculaires. Comptes Rend. 226, 1906-1908 (1948).

(31) A. Coulson and H.C. Longuet-Higgins, The Electronic Structure of Conjugated Systems.

Proc. Roy. Soc. (London), A191, 39-60 (1947).

(32) C.A. Coulson, The Lengths of the Links of Unsaturated Hydrocarbon Molecules.

J. Chem. Phys., 7, 1069-1071 (1939).

(33a) J.E. Lennard-Jones, The Electronic Structure of Some Polyenes and Aromatic

Molecules. I. The Nature of the Links by the Method of

Molecular Orbitals.

Proc. Roy. Soc. (London), A 158, 280-296 (1937).

(33b) J.E. Lennard-Jones and J. Turkevich, The Electronic Structure of Some Polyenes and

Aromatic Molecules. II. The Nature of the Links of Some

Aromatic Molecules.

Proc. Roy. Soc. (London), A 158, 297-305 (1937).

(34) H.H. Greenwood, Computing Methods in Quantum Organic Chemistry.

Wiley-Interscience, London, 1972.

(35) D.W. Rogers, Computational Chemistry Using the PC, 2nd .

VCH Publishers, New York, 1994.

(36a) H.H. Greenwood, T.H.J. Haywood. Properties of the SCF Treatment of Conjugated

Molecules. J. Mol. Phys. 3, 495-509 (1960).

(36b) J.S. Plant, H.H. Greenwood, Hydrogen Bonding in Vitamin B6

. Intern. J. Quant. Chem. 35, 385-393 (1989).

(37) L. Orgel, An Introduction to Transition-Metal Chemistry Ligand-Field Theory.

Menthuen, London, 1960.

(38) See: Interview with W. Kutzelnigg, Bochum, July 24, 1997.

(39) See: Interview with L. Salem, Paris, Oct. 29, 1997.

(40) H.C. Longuet-Higgins and L. Salem, The Alternation of Bond Lengths in Long

Conjugated Chain Molecules.

Proc. Roy. Soc. (London) A 251, 172-185 (1959).

(41) e.g. H. Ahlrichs, W. Kutzelnigg, Ab initio Calculations of Small Hydrides Including

Electron Correlation.

Theor. Chim. Acta, 10, 377-387 (1968).

(42) Kutzelnigg and Förster. Still to be checked in Chem Abstr.

(43) W. Kutzelnigg, Die Lösung des quantenmechanischen Zwei-Elektronenproblems durch

unmittelbare Bestimmung der natürlichen Einelektronenfunktionen.

I. Theorie. Theoret. Chim. Acta, 1, 327-342 (1963).

(44) W. Kutzelnigg, Résolution du problème à deux électrons en mécanique quantique par

détermination directe des orbitales naturelles. II: Application aux états

fondamentaux de l'hélium et des ions isoélectroniques.

Theoret. Chim. Acta, 1, 343-352 (1963).

(45) W. Kutzelnigg, Einführung in die Theoretische Chemie. 2 vol's.

Verlag Chemie, Weinheim, 1975, 1978, resp.

(46) W. Kutzelnigg, Einführung in die Theoretische Chemie. 2 vol's. 2nd Edition.

Verlag Chemie, Weinheim, 1992, 1994, resp.

(47) L. Salem, The Molecular Orbital Theory of Conjugated Systems.

W.A.Benjamin, Inc., New York, 1966.

(48) L. Salem, Electrons in Chemical Reactions: First Principles.

Wiley-Interscience, New York, 1982.

(49) J.A. Pople, D.L. Beveridge, Approximate Molecular Orbital Theories.

McGraw-Hill, New York, 1970.

(50) not quite the proper reference, but similar is:

J.A. Pople, Some deficiencies of MINDO/3 semiempirical theory.

J. Amer. Chem. Soc. 97, 5306-5308 (1975).

(51) N.C. Baird, M.J.S. Dewar, Ground States of s-bonded Molecules.

The MINDO Method and its Application to Hydrocarbons.

J. Chem. Phys., 50, 1262-1280 (1969).

(52) Monsieur Astic is taken here as an example of a technician connected with the general

question on how and by whom the calculations were performed during

the prime time of the Hückel method.

See also: Interview with W. Kutzelnigg, Bochum, July 24, 1997.

(53) Identification of the Menton people (as kindly provided by A. Pullman):

From left to right: Parr, van Vleck, Slater, B. Pullman, A. Pullman, Scrocco.

Mulliken (in a dark suit), Daudel at the center, then B. Wilson (in a dark

suit), followed by Karplus (half-covered), Löwdin, Pople, Pauncz,

Koutecky, Fukui..

(54) R. Daudel, L'Empire des Molécules. Hachette, Paris, 1991.

(55) N. Svartholm, Electronic distribution and chemical reactivity in condensed unsaturated

hydrocarbons. Arkiv Kemi, Min. och Geol., 15A, Nr. 13, 1-13 (1941).

(56) C.A. Coulson, The Theory of the Structure of Free Radicals.

Disc. Faraday Soc., 2, 9-18 (1947).

(57) E. Hückel, Zur Quantenchemie der Doppelbindung.

a) Z. für Physik 60, 423-456 (1930).

E. Hückel, Quantentheoretische Beiträge zum Benzolproblem.

b) Z. für Physik 70, 204-286 (1931).

c) Z. für Physik 72, 310-337 (1931).

d) Z. für Physik 76, 628-648 (1932).

e) Z. für Physik 83, 632-... (1933)

E. Hückel, Grundzüge der Theorie ungesättigter und aromatischer Verbindungen.

f) Z. Elektrochem. 43, 752-788 (1937).

g) Z. Elektrochem. 43, 827-849 (1937).

(58) E. Clar, Aromatische Kohlenwasserstoffe. Springer, Berlin, 1941 and 1952.

(59) M. Zander, Polycyclische Aromaten. B.G.Teubner, Stuttgart, 1995.

(60) R. Daudel, Recent Work of Pascaline Daudel. Polycyclic Hydrocarbons and

Cancer, Vol. 2, p. 37-41. Acad. Press, New York, 1978.

(61) Pullman L-regions.

(62a) for the papers of C. Heidelberger see ref. (2), p. 168 and p. 220 ff, also (62b).

(62b) C. Heidelberger, The Interaction of Carcenogenic Hydrocarbons with Tissues.

V. Some Structural Requirements for the Binding of

1,2,5,6-Dibenzoanthracene. Cancer Research, 18, 1094-1104 (1958)

(63) Crick, Watson and Wilkins were honored in 1962 with the Nobel Prize for their discovery of

the configuration of the DNA.

For an early popular account see:

J.D. Watson, The Double Helix. Weidenfeld and Nicolson, London, 1968.

F.H.C. Crick. Of Molecules and Men. Univ. of Washington Press, Seattle, 1966.

F.H.C. Crick What Mad Pursuit. Basic Books, New York, 1988.

(64) B. Pullman, Reminiscences., Intern. J. Quant. Chem., Symposium 6, 33-45 (1979).

(65) L. Pauling, Introduction to Quantum Mechanics. McGraw-Hill, New York, 1935.

(66) M.J.S. Dewar, A Semiempirical Life. Amer. Chem. Soc., Washington, DC, 1992.

(67) R.S. Mulliken, Life of a Scientist. Springer, Berlin, 1989.

(68) R. McWeeny, Inside story - Some Scientific Reminiscences.

Int. J. Quantum Chem. 60, 3-19 (996).

(69) See Interview with R. McWeeny, September 9, 1993.

(70) R. McWeeny, xxxxxx, Proc. Cambridge Philos. Soc. 45, 315-317 (1949).

(71) B. Pullman, editor of some book on determin chaos???? I think so.

(72) B. Pullman, L'Atome dans l'histoire de la pensée humaine.

(73) G: Berthier, R. Savinelli and A. Pullman,

Theoretical Study of the Binding of the Chloride Anion to Water and

Alcohols. Int. J. Quant. Chem. 63, 567-574 (1991).

(74) e.g. the first paper of the famous series is:

R. Hoffmann, An Extended Hückel Theory. I. Hydrocarbons.

J. Chem. Phys., 39, 1397-1412 (1963).

(75) E. Hückel, Zur modernen Theorie ungesättigter und aromatischer Verbindungen.

Z. Elektrochem. 61, 866-890 (1957).

(76) E. Hückel, Ein Gelehrtenleben - Ernst und Satire.

Verlag Chemie, Weinheim, 1975.





























Appendix I The first three pages of the Thesis of A. Pullman.










Appendix II. A picture from the Menton meeting.

For identification see ref. (53).
















spectral line

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