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Nobel Prizes and Laureates

The Nobel Prize in Chemistry 1996
Robert F. Curl Jr., Sir Harold Kroto, Richard E. Smalley

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Interview Transcript

Transcript from an interview with Harold Kroto at the meeting of Nobel Laureates in Lindau, Germany, June 2000. Interviewer is Astrid Gräslund, Secretary of the Nobel Committee for Chemistry.

Harold Kroto during the interview in Lindau, 2000.


This is Sir Harold Kroto who got the Nobel Prize in Chemistry in 1996 for the discovery of fullerenes. I'm Astrid Gräslund, Secretary of the Nobel Committee for Chemistry, and also Professor of Biophysics at Stockholm University. I would like to ask you some questions. I would like to begin by asking you a little about your background. Where you grew up and where you went to school and then how you became interested in natural sciences.

Sir Harold Kroto: I was bought up in Bolton. Moderate size in the north of England, just north of Manchester. My parents were refugees. My parents were born in Berlin and came to England in 1937 as refugees. I was born in 1939 in the first year of the war. The first month of the war. My parents ended up in Bolton which was a mining and cotton town. There was mining in the area but also weaving which during the period of the decline of the spinning and weaving industry in the UK came into hard times. I lived in the poorer parts of the town because my parents lost more or less everything.

I had a pretty good childhood although we didn't have very much. I was an only child. I went to school and I quite liked school because it seemed better than where I was living. I quite enjoyed going to school. And my parents being refugees really worked very hard to make sure that I did my homework. I wasn't allowed to go to bed until my homework was finished and if it wasn't finished by 12 o'clock my father would finish it off for me. And after a while he was not getting such good marks as I was, so I thought it was time that I would do it by myself.

When I was about 14 or 15 I would work in the factory. I could do everything.

My father was a balloon maker. In Germany in Berlin, before the war, he had printed faces on balloons. When he came to England he lost everything. He became an engineer. I don't know how he managed it. I know a little bit about it. He tried to build up a factory in 1955 to make balloons and he was helped by his old friends in Germany who had made the balloons before. He set up a company in 1955 to make and print balloons. When I was about 14 or 15 I would work in the factory. I could do everything. I think that was extremely good training. You wouldn't be allowed to do this now, because it would be against the safety acts and factory acts. But I could do almost everything. I could repair things. Drill holes. If the machinery stopped I could fix that. I could clean the boiler, which was a big boiler, about half the size of this room. I could take the jets out of the oil pressure /---/. I could mix the dye stuff. Hand in hand with having to do my homework as hard as I could and somewhat pressured, but he was able to help me better with moderately scientific things up to the age of 12 or 13. After that he didn't know things like calculus and things of that sort. From then onwards I would work mainly by myself.

I was interested in art and graphics. I think it's important to me, the most important thing in my life, the thing I'm most keen on is art and graphic design and things of that nature. That went a little bit hand in hand, but I could never have got a job in that area. As I was quite good at sciences at the age of 18 I went to university to do maths, physics, and chemistry. Then to do chemistry as a degree. I wanted to do a PhD in state university because I was having such a good time. I played tennis a lot, actually, and I played for the university and I wanted to stay on and play more tennis and I was also involved with the university magazine doing their designs and covers. So I wanted to stay at the university. It seemed like a good place. It is a good place. And so I got a PhD in chemistry. Then I wanted to live abroad. It was very easy if you had a PhD in those days you could go and do a post doc and my supervisor, Richard Dixon, a professor at Bristol now, found a position for me in Ottawa as a post doc at the National Research Council which was headed by Gerhardt Hertzberg who had created a very effective and outstanding spectroscopy laboratory and I went there. And it was considered the Mecca of spectroscopy. You didn't have to be any good. You must be good if you'd been there and survived. I spent two years there doing more spectroscopy and then I went to Bell Telephone for a year. Then I came back to England.

So your basic degree was in chemistry and then you specialised in spectroscopy after that?

Sir Harold Kroto: My best subjects at school were geography and art and then sciences. We weren't encouraged to consider art as a possible career. We were encouraged to consider going to Oxford and Cambridge, to do Latin or something like that. I went to quite a good school. It was more easy in those days if you passed exams to go to certain schools. This school is now really more of a public school or what you call in the States a private school. I was able to go to this rather good school called Bolton School. I got a few little scholarships worth eight pounds a month or something like that to help. But I was good at chemistry, and gradually ...

You realised chemistry would be your goal.

I don't remember ever consciously thinking chemistry was the thing for me.

Sir Harold Kroto: I don't know how much I realised. It was easier for me. Maths and physics I was good at. Chemistry I don't remember ever consciously thinking chemistry was the thing for me. I wanted to go to university and chemistry was the natural one for me to do. I had several very good chemistry teachers. One was a guy called Jerry who really was quite inspiring. But I had very good physics and maths teachers. Then the last year I had another teacher called Harry Heney who's now a professor at Loughborough. He became a Professor, he left the school only after two years. He probably more than anybody else sent me on this, because he encouraged me to get Feazer and Feazer. An organic textbook to look at. So I got that for my birthday or something. Not many people get thick organic textbooks for their birthday but I got that. it's a very good read. It reads well as well.

I'm not a chemist but I've seen this book. I know it's famous.

Sir Harold Kroto: So I was good at organic chemistry at the time.

Microwave spectroscopy became your speciality at some point?

Sir Harold Kroto: Yes. What happened at university is ... I was introduced to quantum mechanics and the experimental data that underpinned quantum mechanics is spectroscopy and I was in chemistry and I was taught spectroscopy by Richard Dixon as an undergraduate. And I somehow got quite fascinated by it. The fact that a molecule could count, you know there were regular series, beautiful patterns which I got interested in. Although I was very interested in organic chemistry at that time. I thought ... When I wanted to do my PhD I'd like to do spectroscopy. I was in Sheffield where George Porter was, who got the Nobel Prize for flash photolysis, and so it was very exciting time because George had set up all this flash photolysis apparatus. There was that apparatus that belonged to him and Richard Dixon and I worked for Richard but I saw George all the time. He and Richard were quite influential in this.

I enjoyed it. I could play tennis and I could do graphics for the university magazine. I could play the guitar because in those days all the kids at university could play the guitar and sing in folk groups. I was having a good time. and then went to Ottawa to do more flash photolysis. Electronic spectroscopy. After one year in one lab I moved to work with Cec Costain, to do microwave spectroscopy, which is actually a lot simpler than the others. Electronic spectroscopy you have electronic motion, you have vibrational motio,n but in rotational you just have the rotation. So in a sense it's simpler but more precise. And I was a chemist. So you could use microwave spectroscopy to study moderately complex molecules. I started to realise that it would allow me to do chemistry and identify the molecules and study them by what we call microwave spectroscopy.

I read here that in the mid 60s you went to the University of Sussex. Was that for your further academic career?

Sir Harold Kroto: Yes, because I went to do a post doc in Canada at the National Research Council for two years. 1964 to 66. In 67 I went to Bell Telephone for a year. My boss there, Johan Powell, then went to Case Western Reserve, and I had an offer of a post doctoral tutorial fellow. Slightly above a post doctoral fellowship at Sussex. When Johan left to go to Case I thought I'll go back to Sussex. And that's where I went and after half the year I was fortunately, or unfortunately, offered a permanent position there which I took. I spent five years trying to do something as a lecturer at Sussex and if it didn't work I'd probably go and do night school and go into graphics and design. After five years things were starting to tick over. But I would say it took seven years to get really going which is a long time.

It takes a long time if you want to do something new.

Sir Harold Kroto: Well, absolutely, and in fact I think it's tough on modern kids because they're not left that length of time. I did one year as a post doc and then I was given a position which almost was impossible to throw me out. I had some degree of … sort of responsibility to do something. But at the same time I wasn't under the pressure that young kids have to do something and if they don't they get thrown out. I think in many cases, particularly in the USA, the tenure track appointment puts these kids under a lot of pressure which some respond well to and others probably don't respond very well to.

The you also became interested in cosmochemistry. That means the chemistry in the space.

Sir Harold Kroto: In the space ... I would call it interstellar chemistry. Cosmochemistry seems a bit more universal, so it's more immediate than that. I think ... because I was doing microwave spectroscopy or radio spectroscopy one was looking at the radio waves or the microwaves which molecules would absorb. And from that you can tell what they are. I mean in the same way as copper sulphate, the colour of copper sulphate is this rather distinctive blue and so once you've seen it you know that colour is copper sulphate. I mean there are very few other compounds so you can use that to determine it ... use spectroscopy in the optical range to tell you what it is.

... I started to work on phosphorous chemistry which is the area of which I'm most proud as it turns out.

In the same way, in the radio range you can use it to tell you what molecules you've got and you can tell whether you've got ethyl alcohol or ammonia or formaldehyde. And in 1967 or 68 Charles Townes, who invented the laser or maser or both if you wish, made another fantastic advance and he, together with his colleagues, detected water and ammonia in Orion. And this opened Pandora's box because this meant that people in the microwave area could be quite helpful to astronomers using radio telescopes to detect molecules in the interstellar medium. And then in 1974 I started to work on phosphorous chemistry which is the area of which I'm most proud as it turns out. I'm most proud of my work on carbon phosphorous chemistry. But I was also working on carbon chains with a colleague, David Walton, who was an expert in making long carbon chain molecules, and an undergraduate. And we made a moderately long, really it was a short carbon chain, we were able to detect that by radio astronomy in the interstellar medium. And it turns out that in the space between the stars there's huge massive gas clouds which are fairly low temperature but just warm enough so that the molecules can rotate. And as they rotate they give a radio wave and that radio wave you can detect.

Around the 1970s to 1975 there were tremendous advances in our understanding of the space between the stars being made. And we were a part of that, with a colleague Takeishi Oko, a fantastic Japanese scientist, now in Chicago, and astronomers in Canada. We were able to detect several carbon chain molecules and show that there were some interesting species. That was very exciting time. I mean the most exciting time scientifically was the period from 1974 to 1978. That four year period where my work in carbon phosphorous and carbon sulphur chemistry was really exciting. We'd go in and almost every week or month we'd have a new really quite significant result. In 1975, 1976 and 1977 we detected the carbon chain molecule. So that period was for me a golden period. I didn't realise it was a golden period, but in retrospect it was a time of something special. I now look back at it. I can't remember it very well.

Was it very hectic? You were busy all the time?

Sir Harold Kroto: Well, it wasn't. It was hectic, but I had an idea that this would work. A student would have an idea. Results just seemed to pour out during that period in a way that they haven't happened ever since.

But then we come to the question of the discovery of the fullerenes which must have been a very exciting discovery. It was also a short period ...

Sir Harold Kroto: Absolutely. It follows on from the work that Takeishi and I and David Walton did earlier in the 70s in that the carbon chains were there and they presented a bit of a problem because they didn't quite fit with the accepted theories of the way molecules were forming in the interstellar medium. And it seemed to me that they were actually produced in stars. Cool stars. Stars with high carbon content. And they were being blown into the interstellar medium. So there are stars which as they use up the hydrogen to form helium they then go onto a second phase where they use up the helium to form carbon. And at a certain stage they tend to explode and blow the carbon and other elements off into the interstellar medium. But they must be at moderately high pressure and temperature. And it seemed to me that there were going to be conditions in some of these stars, if not all of them, in which carbon chains would form. And therefore what we were seeing was the debris that had been blown out of the stars. That might or might not still be true. We don't know. So I thought this was an interesting idea and I would go to conferences and suggest there's a third way of making these. And in fact a star was detected which showed these things blowing out. But still no one was really paying any attention to it.

Then quite a long time after these discoveries, four years after the last of those in 1979, I was in Rice University and Rick Smalley had developed this fantastic apparatus in which you take a laser to vaporise graphite. Bob Curl whom I was visiting suggested that I go and see him because he'd got this beautiful result on silicon carbide and shown that silicon carbon, the carbon was a triangular molecule. And I thought that was really, really interesting. And as I was talking to Rick and watching him jumping over this fantastic apparatus, because he's a very ebullient and forceful character, I thought maybe if we vaporise graphite we'll produce the carbon chains. We'll simulate the conditions in a carbon star. We'll get a plasma which is similar to the plasma in the intermediate atmosphere of the star. That was a simple idea which could have been done almost on the spot. There were other ramifications... I suggested to Bob Curl and Bob Curl rang me up about 16 months later. It wasn't an experiment that I was rushing around to do. It was an interesting experiment to me. It was less interesting to Rick. But Bob was pretty keen on one aspect of this experiment and I was keen on another, very simple ... both aspects of it. And so in 1985 I got a phone call to go to Rice, either to go to Rice or in fact Shall we send you the results when we get them?

I wanted to do the experiment myself because I was fascinated ...

I made a very important decision. I actually went to Rice University. I wanted to do the experiment myself because I was fascinated. It's also worth pointing out that there's a very good half price book store in Houston which is another reason for going. It wasn't just that I wanted to do the science, I wanted to go to this bookstore. So I had two reasons to go. I think it's important to be aware that I was pretty sure I knew what the answer to the question was going to be. People say there's lots of philosophers of science which says you mustn't do something where you know the answer to the question and in some sense that's true. In this case I knew the answer to the question. I was absolutely certain that Rick Smalley's apparatus would create these things. It's tremendous advance technically because it was the first time you could vaporise refractory materials which are high temperature. It was a major technological advance in what we call cluster science. So I knew it. But even if you know the answer it's probably a little bit of philosophy here. You ought to just check it out for several reasons.

The first reason is it might be true. Fine. Then you can tell, in my case, your colleagues who didn't believe you. Ha, I told you so. You haven't moved on further. You haven't learned anything although you've learned that you're right. But you've not actually made an advance in your own understanding of nature. You've just confirmed your knowledge. That's useful because until you've got that confirmation you don't know that you're right. That's important. The second thing about it is that it might go wrong and it doesn't work and then you know that your other ideas were not right and that you've learned something now. You always learn more from an experiment that goes wrong than you do from an experiment that goes right. If it goes right according to your hypotheses.

So the second one if it goes wrong you've got to find out why it goes wrong. It may go wrong because you haven't done it properly but it may also go wrong because your preconceptions and your received wisdom is incorrect. You definitely learn something in general there. And the third thing is it might go right but something totally unexpected might happen. Of course that's what happened. In that experiment something happened that no one predicted. And in a sense the most important aspect of our discovery is not that this C60 football shaped molecule can be made. It's that it makes itself spontaneously. Perhaps more important than anything else because that was a fundamental paradigm shift in our understanding of carbon. And also sheet materials. So lots of ramifications.

That is also a lesson that you were in a way, even if you didn't expect anything unexpected, when you saw it you were wise enough to realise that it was something worth looking into and not just the noise in the electric current or something.

Sir Harold Kroto: Absolutely. Yes. That's another aspect. Here was a result. You couldn't miss it. Well, we couldn't miss it but other people did. I think again the historical perspective and one important aspect is that the experiment would have been carried out twice before. I first suggested the experiment around Easter of 1984 and when I came back to Sussex at some stage, not that long after, maybe in the summer, Tony Stace, one of my colleagues, gave me a paper by a group at Exxon who had actually vaporised carbon. And it was a remarkable paper. They'd seen some very interesting new species. A whole set of carbon clusters from 30 to 190 maybe. And they were all even. And I looked at this paper and thought: Damn, we could have done this experiment. If only Bob and Rick had listened to me we could have done that the day I was there. It was a very, very easy experiment.

Anyway I read the paper through and there were some interesting aspects. Actually confirmed again more than ever before that the experiment that I wanted to do was perfectly feasible. In fact part of the experiment had been carried out in the sense that it had reacted the carbon clusters with sodium and they'd found that they were clusters which would take up two sodium atoms. And if you have a chain the sodium would go on the end so you'd expect a sodium at each end of this carbon chain so they'd seen something like NA C20 NA, and that seemed to me fit to be fit. But they had this other family of clusters between 30 and 190 and they were all even and they said it was something called carbine. Now I don't believe in carbine actually. It doesn't make any sense, chemical sense. It may be right.

What is carbine?

Sir Harold Kroto: Carbine. It's supposed to be a solid made from polyines and whenever you try to condense polyines they blow up, so if carbine exists at all it can only exist for a very short time before it blows up and cross links to form a highly exothermic reaction in which things blow up. And I've seen these explosions anyway, so I had problems with it. But I thought they were graphite sheets. Sheets of graphite and you could rationalise that a sheet with an even number of atoms would be a little bit more stable than a sheet with an odd number of atoms. I looked at it but I didn't pay a lot of attention to this. I thought that looks like what these things are. I think I should have been smarter than that. I feel I should have looked at that in more detail. Most of the experiment had been carried out. They hadn't done the reactions with hydrogen and nitrogen that I'd wanted to do. There was another group at Bell Labs that also did the same experiment. In the Exxon work they had seen C60. But anyway the Bell Labs had seen C60 and picked it off. In our experiments we carried out some experiments which really changed the conditions. Really pushing this experiment. Not let's do this in random and then rush to the next one. We found that the 60 signal could be made extremely strong. I'm sure if Exxon or Bell had persevered and changed the reaction conditions in the way that we did they would have seen the same results and they would have discovered C60. They would have said this thing is so strong, what structural explanation is there for this strong signal. And they didn't do that. So I wouldn't be sitting here being asked about it because they would have discovered it.

Can I round off by asking ... Now it seems that there are coming some practical applications that you make materials out of ...maybe not balls but at least tubes of this kind of materials. Do you have any ideas about this or would you say it's more of the beauty of nature?

Sir Harold Kroto: I think there's still some major problems to be solved. There is no doubt that the round cages are beautiful and they've changed our understanding of graphite and how graphite behaves, that it can close up into a cage. The nanotubes which were discovered by Japanese Sumio Igima. They're very interesting. They're elongated cages. They bear the same relationship to a dome or a ball as a tube does to these so called nanotubes. They're fascinating. They can conduct like metals you know inorganic super conductor. They're extremely strong. Probably the strongest materials ever made. But to actually use those properties is a major problem which has yet to be solved. And maybe quite difficult. I'm a bit apprehensive that the applications of nanotubes and C60 will be in the near future still have big technological problems. There's always the hint of exciting promise. Getting that promise to the marketplace is another matter.

That is of course something else. Thank you very much.

Sir Harold Kroto: My pleasure.

Thank you very much.

 

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