Interview transcript

I’m very pleased to be sitting here with Professor John Pople at the Lindau meeting, the 50th anniversary of the Nobel Prize Tagungen in Lindau. And let me first ask you, Professor Pople, how did you come to end up in science? Was there a family background in science? What started you?

Professor John Pople: My family has no scientific background. As a child I lived in a small town in the West of England. My father was a shop keeper. He owned and ran the men’s clothing store in this town. My mother’s family were mostly farmers from different parts of England. So I had no professional scientific background in my family. As a child I did become extremely interested in mathematics at about the age of 11 or 12. I was by that time already keeping my father’s accounts, large sums to be added up in pounds, shilling and pence, which is quite complicated mathematics. And I became very facile in doing this sort of thing.

I used to make sometimes deliberate errors in mathematics classes so that I would not appear to be too smart …

But then at the age of 12, when I started being exposed to algebra in school, I became extremely fascinated and spent much of my time teaching myself at the age of 12 more advanced parts of mathematics. In fact, I taught myself calculus using an old book which I found in a waste basket and I took it out of the waste basket and read it from cover to cover. So by the age of 12 I was already actively thinking about mathematical problems. I was thinking about permutations and extending tables of factorials to non-integer values, various projects which I formulated and tried to solve, not always successfully, but I was doing research projects in mathematics when I was quite young. So that was really my introduction to academic subjects. Actually at that age I was quite secretive about it. I did not tell my teachers that I had taught myself calculus. And for a while I was reluctant for this to be known, and I used to make sometimes deliberate errors in mathematics classes so that I would not appear to be too smart. One feels the pressure from one’s peers at that stage. But then after two or three years I sort of went public with this. Then the school authorities, this is at Bristol Grammar School which did have a very fine mathematics teacher, they told me that I should study for the scholarship exam for Cambridge. So I spent the last two or three years really preparing for this competitive intake at Trinity College Cambridge, which is where mathematicians tend to go in Britain, because they have a great history in development of mathematics.

So I went to Cambridge to take the scholarship examinations in the middle of the War, in 1942. At that time it was not too easy to go to University because almost all young men, I was 17 at the time, were conscripted into the army. But there was a programme for a small number of mathematics students to go to university, to Cambridge, to take a mathematics degree in a very short compressed period and then go into government service in some form of operations, research. This turned out to be a very successful programme. Some of the people who were in the programme before me that were older than me had made major contributions to the British war effort. Freeman Dyson was one such person. He was in exactly the same programme two years older than me, and he was in Cambridge between 1941 and 1943, and I think he went on to become an adviser to the air force in the latter part of the war. In my case I went to Cambridge in 1943 and by the time I’d completed my degree in 1945 the war was just ending so I never really did anything useful in the war time.

Turing did also at that time.

Professor John Pople: Well Turing, yes. I never met Turing. Turing was older than me. In fact, he was already a significant mathematician before the war, some very famous publications of his in the late thirties. Then right through the war of course he was a key figure in the code breaking operations and had an immense impact on the subsequent history, probably the most influential mathematician in modern times in that sense. Without his code breaking developments in the middle of the war it may well have gone the other way. It’s quite remarkable.

Then you went on to PhD studies?

Professor John Pople: Yes, in 1945 as the war was ending I was, the government didn’t quite know what to do with me because the war effort was winding down. So I was sent off into industry and I worked for the Bristol Aeroplane Company for two years, not doing anything very significant, until I could get back to Cambridge to start a research career. And so I returned in 1947. I spent one year doing sort of post graduate courses in all branches of applied mathematics and then it was after that that I decided to become a theoretical scientist. And at that point I picked on chemistry as a field that I would enter. But until then I had no background in chemistry. I’d given up chemistry at a quite early stage in high school. I decided this was a good opportunity. It turned out well.

But eventually you went to Canada for a while.

Professor John Pople: Yes, that’s correct. So from 1951 I became a research fellow at Trinity College and then two or three years later I actually became a faculty member in mathematics in Cambridge, so I taught mathematics from 1954. And it was at that time that I accepted an offer to go for two summers to the National Research Council in Ottawa. That is the point at which I became interested in nuclear magnetic resonance, largely because they were just starting there and they had some very interesting results and I had some ideas on it. So I spent two or three very fruitful years, spending the summers in Canada and going back and doing my teaching in Cambridge during the rest of the academic year.

I think that for me it started very early, NMR. And the book you wrote together with Schneider and Bernstein was, I think, to me the revelation of what NMR was. You laid the ground work for …

Professor John Pople: Yes, that was very … at that time, that was very well timed. The objective when we started, we started in 1957 I think, we said we would try to write a book which covered everything that had been written on nuclear magnetic resonance, high resolution nuclear magnetic resonance. And we actually attempted to refer to every paper on the subject.  And we did that. We later discovered we’d missed two in the rush. But when the book was completed, it was only just possible because in the next six months the literature exploded. But it was early days. You could write interesting papers on very simple spectra of very simple organic compounds. We used to go down the corridor and knock on the door of an organic chemist and look along his shelf and say “Two three lutidine, let’s take that compound.” I’d go away and write a paper on it. The chemist would say “Well, what do you want that for?”.

Also you started working on quantum chemical methods and development on computational techniques?

I used to switch from one topic to another every two or three years …

Professor John Pople: Yes. In the early days a felt that a theoretical chemist should really address all branches of chemistry and I did work as I told you on liquids, statistical mechanics or liquids. And I also started doing some work on quantum mechanics, there’s early papers on that by 1952. And then I did the nuclear magnetic resonance. So I used to switch from one topic to another every two or three years. But that became more and more difficult I think because as fields grow you need a great deal of technical expertise.

So in 1958 I took an administrative job which was for several years which I didn’t like very much. And when I gave that up I decided that I would return to full time research, with the main emphasis on quantum mechanics, of electronic structure of molecules, which is the most fundamental part of theoretical chemistry, basic understanding of how molecules, why molecules behave as they do. So that is the time at which I moved with my family to the United States.  And the projects for which the Nobel Prize was awarded were started around that time.

The Gaussian program which just transformed quantum chemistry completely. Actually, you have seen the development of quantum chemistry problems, fairly a small group of people using it, now it’s a kind of standard technique. How would you see also the future development of quantum chemistry? Computers will soon evolve and you have some gigaflop or teraflop computers coming in the future. Will that per se also influence quantum chemistry or are there still more technical developments that are equal important?

Professor John Pople: Progress has taken place in both respects. One has been able to achieve more efficient or new methods, or more efficient ways of handling the same method. Certain theoretical computations may start off being rather expensive and hard to use except for very small molecules. But then one can do a lot of research on new mathematical schemes which will get the same answer with far fewer operations. That has been a major focus of work and that has enabled the techniques to be applied not only to very small molecules but to many molecules, larger molecules, and to begin to make really significant predictions about chemical behaviour. And that will certainly continue. Computers are clearly going to get faster and faster and we are continually working on ways of making our methods used to fewer and fewer multiplications to get bigger and bigger systems. So this is very much a development along the same path. You can never tell whether a totally new method will come in and demolish all existing procedures, but I don’t see it at the moment.

Would you see for example a kind of fusion of molecular dynamics and quantum chemistry?

Professor John Pople: Yes, that’s right. The good quantum chemistry, high level theories can still only be applied to systems of up to maybe 100 electrons. And it’s important to be able to examine systems which are in solution for example, where you have to take account of all the rest of the material. So there’s important work going on on kind of multiple techniques where you use a quantum mechanical study of, a good quantum mechanical study of a central part of a molecule or system, that you need to study carefully. And it’s surrounded by a solvent or the rest of a large protein or something which are simulated in a cruder fashion so that you can still get the general effects of the medium on the chemistry that’s going on.

At this meeting many things have also happened. Two days ago there was a joint announcement by groups from the States and Britain and other countries that have completed the sequence for 99 or 97% of the human genome. It’s regarded by many as a milestone in the human history, science history. And probably rightly so. I know that you take an interest also in biological systems and would you like to comment on these recent events that we have witnessed?

Professor John Pople: Yes, well that is certainly the complete knowledge of the human genome would be a big step forward. I think from a scientific point of view one may well desire to have the sequences of many more species before we can begin to really get a further understanding of evolutionary processes and how they have taken place. Biology is really a giant study in the history of particular chemical reactions which has gone on for three to four billion years over a complicated fashion. And the fundamentally interesting point is how did this come about and how did it develop in its various branches. And we’ve heard something of this of course in the talks this morning. So I think this is a big development. It’s clearly the way that the future of the science will go. I’m sure there’ll be the sort of political pressure to work primarily on the human condition rather than other species, which might be more informative, and on which one might be able to do it as was pointed out this morning, on which it might be possible to do more actual experiments.

You have had a lot of students over the years, what advice have you given them during their carreer?

… research is all about getting new ideas …

Professor John Pople: For my students? Well I’ve had a very fine set of students. I’ve always tried to advise them to handle research in an innovative but critical manner. It’s all about, research is all about getting new ideas. It’s always desirable to question existing ideas. It’s always desirable to formulate your ideas in as simple a fashion as possible, to test them as carefully and as fully as possible for the whole series of steps which I think constitute good research. And many of my students, I think, are very proud of their subsequent careers, have done very well. I’ve got to the age where I actually find myself going to dinners for retirement of people who were students of mine. So after one’s own retirement one starts attending other people’s retirements or 60th birthdays and all those things.

You are still active as a scientist.

Professor John Pople: Yes, I’m active part time. I no longer run a large research group but I do have some collaborations going and I am part of a commercial company which is in the business of distributing programmes of this sort. So that keeps me active, as well as attending Nobel functions which is a major part of one’s life.

That’s exciting. Thank you very much, Professor Pople.

Professor John Pople: Thank you.

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