00:00:41 Professor Sir George Porter was born in Stainforth, Yorkshire, England, in December 1920.

00:00:45 to John Smith and Alice Ann Porter.

00:00:48 Sir George attended Thorne Grammar School, Leeds University, and pursued graduate studies

00:00:53 at Emanuel College and Cambridge.

00:00:57 During World War II, he served in the Royal Navy.

00:01:01 George Porter is known internationally for his work in chemistry education, particularly

00:01:06 his series of BBC television lectures entitled The Laws of Disorder.

00:01:13 Sir George has held a number of influential positions in the chemistry community, including

00:01:18 Assistant Research Director at Cambridge University, Assistant Director of the British Rayon Research

00:01:24 Association, Professor of Physical Chemistry at Sheffield University, and Professor and

00:01:30 later Director of the Royal Institution.

00:01:34 In 1967, Sir George Porter shared the Nobel Prize in Chemistry with his long-time mentor

00:01:40 RGW Norrish and collaborator Manfred Eigen for their combined work on studies in flash

00:01:48 photolysis, a technique that initiates and records very fast chemical reactions.

00:01:56 In this program, Sir George Porter is interviewed by Ms. Moira Donnelly, Public Affairs Officer

00:02:02 of the Royal Society of Chemistry at Sir George's offices at the Royal Institute.

00:02:10 After you left the Navy, you went back to Cambridge and began work on flash photolysis

00:02:16 very quickly thereafter.

00:02:18 That's right, yes.

00:02:20 I had, I was a chemist and I had decided, I had a lot of time to think in the Navy,

00:02:28 and long hours at sea in the hammock.

00:02:32 And I decided that certainly I wanted to do research.

00:02:39 And I decided the action was on the periphery, to some extent, of chemistry, on the physics

00:02:44 side or on the biological side.

00:02:46 I wasn't quite sure which, still aren't, I think they're both important.

00:02:51 Did you have an idea of the project you were going to do, or was it just a general area

00:02:55 for search?

00:02:56 No, I, apart from that, I, that meant that I decided I wanted to go to the physical chemistry

00:03:04 department or perhaps to the physiology department.

00:03:08 But I did, in fact, nearly do that.

00:03:11 I did have some correspondence with Lord Adrian, as he later became.

00:03:19 But in the event, I went to see Professor Norrish in physical chemistry and found myself

00:03:29 very interested in photochemistry, which was his main field.

00:03:32 I had, of course, heard the name as an undergraduate.

00:03:36 So I decided to do photochemistry and began by throwing myself into the things which were

00:03:44 going on at that time there.

00:03:47 What we were going to do was try to look at free radicals directly.

00:03:52 Free radicals were the great thing in reaction kinetics at the time.

00:03:58 And he thought that by having a very intense light source, we would get a high enough concentration

00:04:03 to see them.

00:04:04 But that wasn't so, because the lifetime was so short.

00:04:10 And it wasn't, the carbon arc was mainly heat and very little light.

00:04:16 So I replaced that with a seven kilowatt mercury lamp, which was better.

00:04:24 It was more ultraviolet, but still a continuous source.

00:04:28 And that blew up and I had to go to Siemens Lamp Works in Preston to get another one quickly.

00:04:36 And it was there that I was shown around the factory and saw the very powerful flash lamps,

00:04:45 which they'd been using for aerial photography and so forth.

00:04:50 Now really, I would have been stupid not to see the connection.

00:04:54 I was looking for free radicals which lasted for only a thousandth of a second or less.

00:05:02 It's really pointless just to pour continuous lighting to see something for a thousandth

00:05:08 of a second.

00:05:09 What you need is a much more intense thing for a thousandth of a second, and that's just

00:05:12 what the flash was.

00:05:14 And so, having nothing else to do, after I'd been to the factory, what else can you do

00:05:21 in the station hotel in Preston?

00:05:26 I sat down and thought this out in some detail, and when I went back the following day I put

00:05:33 a proposal to Norrish that this is what I wanted to drop my searchlight and the cranking

00:05:39 of the diesel and try the flash lamps, which he accepted immediately as being a very good

00:05:46 thing to try.

00:05:48 So you had your light source, that was one problem, but you also had to find a way of

00:05:52 measuring these reactions.

00:05:54 Was that a problem too?

00:05:55 It was a very big one.

00:05:58 I wasted, really I suppose I wasted a lot of time, certainly it wasn't entirely a waste,

00:06:04 but all right, I had the flash and eventually got that working with these condensers and

00:06:11 so forth, and then how do you measure it?

00:06:14 And thinking of radar, I thought of an electronic method of doing it with a scanning spectrograph,

00:06:33 and I built, I tried to build, I did build a scanning spectrograph, that is to say I

00:06:37 had a grating spectrograph with a rotating mirror in it which scanned the spectrum sort

00:06:43 of continuously, so that I tried to get the whole spectrum after the flash.

00:06:51 And that wasn't the way to do it, though it just wasn't the time resolution of a scanning,

00:06:56 nor was the intensity to do it.

00:06:59 I was trying to get too much information, I was trying to do, with one flash I was then

00:07:03 trying to whizz round, whizz through the whole spectrum with the mirror and get the whole

00:07:07 spectrum, and that meant moving very quickly and very poor resolution, and it was, it was

00:07:16 a difficult thing to build and it wasn't a very, it worked, it wasn't a very successful

00:07:20 instrument.

00:07:21 It was one of the first scanning spectroscopes, but it wasn't a very successful instrument.

00:07:27 And then in using the flash I was getting, in any case, by scattered light I was getting

00:07:35 beautiful continuous spectra and I suddenly thought, well that's what I need really.

00:07:41 And I then had, which really the second part of the idea came in two parts, and the second

00:07:49 very successful one was to use a second flash, just the same as the first but weaker, and

00:07:56 delayed.

00:07:57 I did the delay by a spinning wheel which, with contacts on it, an idea which had come

00:08:03 from an American radar set which, instead of using electronic valves, used a spinning

00:08:09 wheel, it was called the SL, and I used that.

00:08:13 So I had two contacts on the spinning wheel, the first contact fired the big flash which

00:08:17 produced the radicals, and then as the wheel turned round, the second contact fired the

00:08:23 second flash, and that was that, and I got the whole spectrum, say a thousandth of a

00:08:29 second later.

00:08:30 And then I moved the second contact slightly round the wheel to two milliseconds, two thousandths

00:08:36 of a second, and got the second whole spectrum and so on.

00:08:40 That was very much better information theory because I was again using a flash, instead

00:08:47 of trying to use a continuous light, I was using a flash for the second recording part

00:08:54 of the experiment as well, and that worked.

00:08:57 The first really exciting radical that I got was CLO.

00:09:13 Fred Dainton, Professor Dainton, Dr. Dainton as he then was, was looking at the carbon

00:09:18 monoxide chlorine reaction, and I thought I would look at that, look for the COCL radical.

00:09:27 I didn't get the COCL radical, but there were changes.

00:09:31 But when I had some oxygen in it as well, I got a beautiful new spectrum, and then when

00:09:38 I took the carbon monoxide out, I still got the beautiful new spectrum, so I was getting

00:09:41 it from just chlorine and oxygen.

00:09:45 And it was fairly obviously a diatomic molecule, if you have chlorine and oxygen and it's diatomic,

00:09:52 you don't have a lot of choice, you don't have a lot of options, and it was in fact

00:09:56 CLO which hadn't been observed before.

00:09:58 So because that's very exciting.

00:09:59 It was very exciting because it's a beautiful spectrum.

00:10:02 I was able to do it, it lasted about five milliseconds, which in those days was a nice

00:10:09 long time for my apparatus, my apparatus was only good for about a millisecond, so

00:10:15 I had plenty of time to study it.

00:10:18 And I was able to do some good kinetics on it, it disappeared by two CLO molecules coming

00:10:24 together and making, the whole thing reverses, that's another nice thing about it.

00:10:29 You could go on with the same mixture, it was a totally reversible reaction, after less

00:10:36 than a second it was back where it started, so you could go on using the same mixture

00:10:39 all the time.

00:10:40 Very economical.

00:10:41 Very economical.

00:10:42 But it was really very exciting to take, I took, these were ten inch plates in the spectrograph

00:10:49 to take this ten inch plate into the dark room and under the red light see this beautiful

00:10:55 series of bands coming up and disappearing in about five milliseconds and so on.

00:11:00 So I spent quite a bit of time on that, analysing the spectrum, which told us a lot about the

00:11:05 CLO, and then looking at the kinetics of the decay, and it was very nice, it produced some

00:11:17 nice fundamental results, absolutely useless of course, so it appeared.

00:11:22 The funny thing is, the way it's turned out, you never know, do you?

00:11:31 The hole of the Antarctic, the ozone hole, is due to CLO.

00:11:38 There it is, destroying the ozone over the Antarctic and in other parts.

00:11:43 The CLO radical plays the part of the NO radical, NO does the same thing, and of course is made

00:11:51 from the chlorine which comes from the chlorofluorocarbons, from aerosol sprays and so forth.

00:11:57 So immediately this danger was perceived of the chlorofluorocarbons making chlorine

00:12:05 in the stratosphere and destroying the ozone there, immediately that was perceived, information

00:12:10 was needed about the CLO radical, which is the heart of the matter, and it was all there,

00:12:17 thirty years later.

00:12:18 That's wonderful, isn't it?

00:12:20 What I didn't realize perhaps is, well, how it would develop.

00:12:27 In two ways, firstly that it would be extended to many things apart from free radicals, almost

00:12:32 anything produced by light which lives for a short time.

00:12:37 But secondly, I didn't know that the laser was going to be invented and that the flashes

00:12:48 would become, instead of milliseconds and microseconds, would become nanoseconds and

00:12:53 picoseconds and photoseconds.

00:12:56 And that's been the exciting thing since, of course, that it's been possible to get

00:13:00 shorter and shorter and more and more powerful flashes.

00:13:04 And so the whole pulse and probe technique is what it is really, or the double flash

00:13:11 technique is what is used now in all these regions with lasers.

00:13:17 Was there anything else that you did in the period at Cambridge which was significant,

00:13:22 or was it just building on the early work?

00:13:25 No.

00:13:26 There was, I mean, yes.

00:13:28 There was one other totally different field, yes, which pleased me very much at the time.

00:13:40 G. N. Lewis had done some work at the beginning, early years of the war.

00:13:48 He died shortly afterwards, on frozen glasses, organic glasses at liquid nitrogen temperature.

00:14:01 And it occurred to me, in fact Lewis had, as I discovered later, had done some rather

00:14:09 similar experiments on much more stable radicals to the ones I was proposing.

00:14:13 But it occurred to me, why don't I put one of these molecules which produces a free radical,

00:14:25 like acetone or chlorine dioxide to get the CLO, which in fact is the first one I did,

00:14:35 into a frozen glass at liquid nitrogen temperature and irradiate it and hope that it will be

00:14:41 broken up, but then the bits that fly off will be frozen in separately in the glass

00:14:46 and it will be there forever.

00:14:50 And would it be there forever?

00:14:52 Well, you think.

00:14:53 Look at a stained glass window.

00:14:55 A stained glass window has these pigments in it, molecules quite close together, and

00:15:02 yet over thousands of years they don't diffuse and merge.

00:15:07 So why not?

00:15:09 And an American post-doc came to work with me for a year, Irwin Norman, and I suggested

00:15:18 that he might try this.

00:15:21 And after breaking a lot of courts' duels and this sort of thing, we got that to work

00:15:26 as well.

00:15:27 This was all about the time that the triplet state was coming along.

00:15:31 It was a very exciting time with the flash photos.

00:15:35 And sure enough, he put CLO2 in, and we got the CLO radical, there forever now.

00:15:42 He called it trapped radicals in glasses, a letter to nature, trapped radicals in glasses.

00:15:49 And it became a very, quite a big thing.

00:15:53 There were other approaches to it which followed very closely afterwards, quite independently.

00:15:58 Breuder was one who, they called it matrix isolation.

00:16:04 They passed the material along a hot tube and then trapped the radicals on a cold finger,

00:16:14 whereas I was doing it in situ by shining light on them.

00:16:19 But this, in fact, there was a great excitement around that time because they were going to

00:16:25 use them as rocket fuels.

00:16:26 They thought if they could freeze enough radicals, there's a lot of stored power there, and they

00:16:30 could use them as rocket fuels.

00:16:31 That never turned out to be important.

00:16:34 But it is a much-used technique to this day.

00:16:38 It's a way of looking at unstable molecules by producing them by light or other methods.

00:16:44 In Sheffield, you, of course, gathered quite a large group of people around you.

00:16:49 You were diversifying, obviously.

00:16:52 Can you tell me a little bit more about what was going on in Sheffield?

00:16:57 Well, it was the triplet state work that I mentioned was only just begun.

00:17:05 We'd hardly begun it in Cambridge.

00:17:07 We'd shown that it worked, and then we moved to Sheffield, and nearly all the triplet state

00:17:12 work.

00:17:13 There's an enormous amount of, I mean, the triplet state is a whole major area of photochemistry

00:17:24 and even chemistry.

00:17:26 So there were all sorts of aspects of that, how it disappeared, radiation-less processes

00:17:34 of jumping from one state to another, quenching, exit on annihilation between two excited states

00:17:47 and so forth.

00:17:48 All these things were studied in that time in Sheffield.

00:17:53 As I said, I began, we built our first laser apparatus there, which then developed when

00:18:01 I got to the Royal Institution.

00:18:05 And I began my interest in photosynthesis there.

00:18:09 We began to look at, to do flash photosynthesis under the microscope on single cells of chloroplasts

00:18:18 of the green leaf, which I continued to do ever since.

00:18:23 Were you sorry to leave Sheffield?

00:18:25 I mean, did you have any ambivalence about leaving Sheffield to come to the RI?

00:18:30 Not really, no.

00:18:31 I mean, I liked Sheffield.

00:18:32 It's not to say I didn't like Sheffield, but I'd been there 11 years.

00:18:35 I was the head of the chemistry department.

00:18:37 I didn't want to be a dean, which I was just about going to be if I'd stayed there.

00:18:43 I didn't want to be a vice-chancellor anywhere else and so forth.

00:18:48 So that really the only thing to do would be to move to another chair of chemistry in

00:18:55 another university or to the Royal Institution, which was very much on my mind because I had

00:19:05 given some lectures there and I was a professor there in the sense that it was a sort of honorary,

00:19:11 well, not honorary in the sense that I was paid for the hard lecture that I gave there.

00:19:16 And I gave a couple of discourses and some schools lectures and I got very excited.

00:19:22 It was a marvellous place.

00:19:23 I got very excited about that.

00:19:27 By this time I was really enjoying lecturing and quite enjoying popular lectures and in

00:19:36 fact during the last two years I was at Sheffield, I did a very extensive television series called

00:19:48 The Laws of Disorder, which was very successful.

00:19:53 It was shown four times on BBC television and this was in the days of black and white

00:20:02 and only one channel.

00:20:04 So everybody had to watch it, you see, because they had no choice.

00:20:08 So everybody saw this.

00:20:09 It must have been, of all the scientific lectures I've given, I suppose it got the biggest audience

00:20:14 of the lot.

00:20:15 And I enjoyed this so much and the Royal Institution, I didn't do that at the Royal Institution,

00:20:21 but the Royal Institution was obviously a place where people had, like Faraday and people

00:20:27 that no one could possibly live up to, had managed to do popular lectures and so forth

00:20:33 and pretty good research.

00:20:36 So I thought this would be something exciting and I would try it when I was offered the job.

00:20:42 How did you come to make the television series?

00:20:47 Did someone approach you?

00:20:49 Was it your idea or how did this come about?

00:20:51 I mean it seems quite an extraordinary subject for a television series.

00:20:56 Like everything else, one thing grows out of another.

00:21:00 The sequence is very simple.

00:21:02 I had to give, like everybody else, an inaugural lecture at the Royal Institution, sorry, an

00:21:08 inaugural lecture at Sheffield, and I became a professor there.

00:21:12 There were so many professors being appointed that my inaugural lecture was given after

00:21:15 I'd been there about seven years.

00:21:19 And the Vice-Chancellor, Dr. Whittaker, said, now let's have something exciting, let's have

00:21:28 lots of demonstrations.

00:21:31 And I said, I don't know if I can really do demonstrations, physical chemistry, you know,

00:21:36 thermodynamics, it's very difficult.

00:21:39 And he said, you can, I've seen it, and they're very good.

00:21:41 Let's have some bands and things.

00:21:43 He's a mathematician, a very academic person, but he wanted this and I thought, well if

00:21:48 the Vice-Chancellor wants it, I'll try it.

00:21:49 So I put a lot of effort into it, and I did a rather spectacular inaugural lecture, which

00:22:00 I was immediately asked to give again at various places and so on, but particularly one of

00:22:07 the Sheffield people told Sir Lawrence Bragg about it, and he invited me to give a discourse

00:22:13 at the Royal Institution.

00:22:14 I hadn't lectured at the Royal Institution, and I gave more or less this inaugural lecture

00:22:20 as the discourse, and they liked it, and Sir Lawrence asked me whether I would be a professor

00:22:28 at the Royal Institution, so I did a number.

00:22:31 And about two years later, it was my turn to give a discourse again, we don't give those

00:22:37 too often, and I got together one on thermodynamics, which sounds the most unpromising subject

00:22:45 for a popular lecture, and I called it The Laws of Disorder, and of course a lot of people

00:22:51 go from all over the place, go to these lectures, and among the audience was a person called

00:22:59 Philip Daly, in the BBC, who I was a great admirer of, or I have been, he's died recently,

00:23:11 he was a pioneer of science on television, and he asked me would I consider doing a whole

00:23:15 series on this.

00:23:16 I had done one programme before, that wasn't my first, I did one, there was a series on

00:23:21 BBC television in those days called Eye on Research, and they came to Sheffield and did

00:23:28 one on the, it was called Quick as a Flash, on my research.

00:23:37 And I put a lot of effort into that, as a matter of fact, it wasn't just lecturing on

00:23:43 what I knew, I tried to think out new approaches to some parts of thermodynamics which would

00:23:51 be understood by the non-scientist.

00:23:57 I had a lot of demonstrations, but I particularly approached thermodynamics as well as the title

00:24:04 The Laws of Disorder implies, as through entropy being a mixed-upness, a chaos, and how to

00:24:12 measure that, and with examples from things that people are familiar with, like games

00:24:18 of cards, and dice, and that sort of thing, and so that's how it happened.

00:24:28 We didn't talk very much about the time at the RI, apart from the lectures, you did do

00:24:36 some quite interesting work while you were at the Royal Institution, and you were there

00:24:39 for quite a long time.

00:24:41 Twenty years.

00:24:42 Yes.

00:24:43 Do you want to talk a little bit about the days at the Royal Institution?

00:24:48 About the research, you mean?

00:24:49 Yes, about the research for other aspects of it.

00:24:50 Because we were talking about, I was doing a lot of lecturing and that sort of thing,

00:24:58 and taking an interest in the RI itself, which is extremely interesting, looking after lectures

00:25:06 given by others and so forth, but research was my main activity there, really, and the

00:25:16 two main developments there were, it was at the RI, really, that we went into the laser

00:25:26 development of flash photolysis.

00:25:31 We built the first nanosecond apparatus there, with the first Q-switched laser, and we first

00:25:39 observed the singlet state, which I was talking about earlier, the very much short-lived singlet

00:25:44 state there, and then into the picosecond region, and now into the femtosecond region.

00:25:52 All this is, it takes time, and it, one can't, it was now so well, it was so obvious that

00:26:06 this is what would happen, it depended on the new lasers and so on, that I can't claim,

00:26:12 nobody can claim that they were leading the field here, it was a number of people right

00:26:19 at the front, pushing on in different directions, so I can't claim that we were the first in

00:26:25 the nanosecond or picosecond, I don't think anybody can, because it was all going parallel,

00:26:30 and it's still developing.

00:26:32 But it is a very important development, and it was fun, there were a lot of new areas

00:26:38 that were opened up, and most of all, that's the second thing, it then became possible

00:26:44 to study photosynthesis, which is the, really the most, certainly the most important photochemical

00:26:53 reaction, it's probably the most important chemical reaction, it's almost the most important

00:26:58 thing that happens, because it's the origin of life, and it provides all our food and

00:27:03 energy for life.

00:27:05 You spent 20 years at the Royal Institution, was there any question at all about you not

00:27:11 coming to the Royal Society, I mean, you were elected and then took up the position here

00:27:17 in the last, you took it up a couple of years ago.

00:27:20 That's right, yes, not really, I mean, it's a very great honour indeed, and one Faraday

00:27:32 refused it, but he was getting, he felt he couldn't do it, he was getting a bit over

00:27:39 it and so forth.

00:27:40 Now, I didn't feel I could refuse it, but on the other hand, it is, I, there are problems,

00:27:50 I couldn't do the, I couldn't continue to be Director of the Royal, I should have been

00:27:53 Director, still Director of the Royal Institution today, because I haven't reached retiring

00:27:58 yet, quite, I nearly have.

00:28:01 But I, when I was asked about it, I, they said, well, what are you going to do about

00:28:05 the Royal Institution, and I said, well, I can't do both, and I'll have to give up the

00:28:08 Royal Institution, although I want to continue my research, I still have, in fact, I've moved

00:28:13 my research now from the Royal Institution to Imperial College, and I've got a little

00:28:17 group of five students, well, two, three students and two postdocs working with me there.

00:28:25 I've got a nice new lab, and I hope to go on doing that for a few more years, but I

00:28:31 couldn't, this is the Royal Society Presidency today, it's getting busier and busier, and

00:28:37 we're doing more and more things, and it's almost a full-time job.

00:28:41 Of course, it's an honorary job, too, that's another.

00:28:43 No salary.

00:28:44 No salary, yes, but it's, it's so important, and it's, looking at the, my great predecessors,

00:28:53 it's something that no scientist, I think, would want to refuse.

00:28:59 Do you have any advice that you'd give to people contemplating a career in science now?

00:29:06 Yes, go ahead.

00:29:10 I think it's a marvellous life, I couldn't have been happier.

00:29:17 I can't think of any other life, absolutely no other, I mean, however successful I might

00:29:23 have been, Prime Minister or whatever, nothing would have given me as much real satisfaction,

00:29:29 deep satisfaction, as science, the pursuit of knowledge, even if one only makes, dots

00:29:39 a few I's and crosses a few T's, even if one makes only a very small contribution, it is

00:29:44 a permanent contribution to, to the advancement of mankind, if, to discover something.

00:29:52 I'm not sure that there, you can say that of any other field, really.

00:29:57 And physical chemistry, which was your field?

00:30:00 Well, I, in any, in any proper science, which is, which is based on the scientific method,

00:30:12 that is to say, it is assessed by other scientists and thrown backwards and forwards so that

00:30:19 it is really, it is really a true advance of knowledge, physical chemistry is just one

00:30:28 of those.

00:30:29 As far as physical chemistry is concerned, if you mean would I advise somebody to do

00:30:34 physical chemistry, yes, because physical chemistry is very basic science which can

00:30:39 be applied to the upper atmosphere or to the lowest plant or the lowest animal.

00:30:49 I do think right now, in fact I've shifted my research towards photosynthesis, as I said,

00:30:56 I do think right now the action is on the biological side, but it's the biological side

00:31:03 using physics and chemistry, it's, it's not stamp collecting or plant collecting anymore,

00:31:10 it is biophysics and biochemistry where the advances are being made, but by the time a

00:31:18 ten-year-old today is doing his research at the age of twenty-five it may be different.

00:31:25 Perhaps it will come back to fundamental particle physics, which at the moment I don't find

00:31:31 very exciting, I feel that there isn't the equivalent advance occurring there which was

00:31:39 happening in the twenties and early thirties, for example.

00:31:43 So I, my choice at the moment would certainly be on the biophysics, biochemistry, biological

00:31:48 side where enormous advances are being made.

00:31:52 Well, Professor Sir George Porter, thank you very much.