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00:00:30 George Claude Pimentel was born in Rolinda, California in 1922

00:00:36 and received his A.B. from the University of California, Los Angeles in 1943

00:00:42 and his Ph.D. in 1949.

00:00:46 Dr. Pimentel is best known for his work with chemical lasers,

00:00:50 although his research spans the breadth of the chemical sciences.

00:00:55 In the 1940s, he worked as a research assistant on the Manhattan Project

00:00:59 and later joined the nuclear physics section at the Office of Naval Research.

00:01:04 In 1949, he became chemistry instructor at the University of California, Berkeley

00:01:10 and remained there for the rest of his career.

00:01:13 Dr. Pimentel pioneered research in matrix isolation,

00:01:16 which permits a more leisurely spectroscopic study of highly reactive molecules.

00:01:21 He developed chemical lasers, which permit the study of reaction dynamics

00:01:26 and vibrational energy transfer, and rapid scan infrared spectroscopy,

00:01:32 which permitted the analysis of the Martian atmosphere

00:01:36 during the Mariner 6 and 7 space missions in the early 70s.

00:01:41 Dr. Pimentel has published numerous books and articles on chemistry.

00:01:45 Chief among them are his work with A.L. McClellan,

00:01:49 The Hydrogen Bond, and the ChemStudy films,

00:01:53 which revolutionized the study of chemistry in American high schools in the 60s

00:01:58 and is still widely used today.

00:02:00 In this interview, Dr. Pimentel reminisces about his life and work in chemistry.

00:02:07 The interviewer is Professor Andrew Stern of the Graduate School of Journalism

00:02:12 at the University of California, Berkeley.

00:02:16 I was fortunate in that my parents were both intelligent people

00:02:22 and had this very strong emphasis on the importance of my brother

00:02:27 and me getting as much education as possible.

00:02:31 Each of them, my mother and my father,

00:02:34 sensed how much they had lost by not having any education.

00:02:38 And so even though there was not an academic environment by any means,

00:02:43 and neither my father nor my mother had any significant education,

00:02:49 the emphasis was always on getting education.

00:02:54 As my father used to say,

00:02:56 so you don't have to work with your hands the way I do.

00:03:00 But my specific interest in science developed in high school

00:03:05 mainly because I found the math and physics and chemistry most challenging

00:03:10 of the courses I took.

00:03:11 There wasn't any particular teacher in high school who had big influence on me.

00:03:17 It was more the challenge of the subject matter.

00:03:20 Why did you pick UCLA?

00:03:23 Well, at the time, that was the only way I could go to college.

00:03:26 It was this business of the Depression years,

00:03:31 and there was no chance.

00:03:33 We lived only six miles from Caltech,

00:03:35 but there was a tuition there.

00:03:38 And so what I did was live at home,

00:03:42 so I got free room and board,

00:03:44 all the way on the other side of Los Angeles from UCLA,

00:03:49 and I commuted every day.

00:03:51 How did you commute?

00:03:52 Well, I bought a car with my earnings my first summer,

00:03:57 and I bought a four-door

00:04:00 so that I could carry as many passengers as possible,

00:04:03 and fellow students who were commuting

00:04:06 each gave me some amount, 25 cents each or something,

00:04:10 and that paid for gas.

00:04:11 And so then it was just a matter of incidental monies.

00:04:17 After I got to the junior level,

00:04:20 UCLA was a marvelous place for an undergraduate at the time

00:04:24 because they had few graduate students.

00:04:27 They brought what they considered

00:04:30 to be promising young undergraduates

00:04:32 into the teaching activities.

00:04:34 So from then on, I was engaged

00:04:36 in some kind of teaching activity during the summers.

00:04:40 Graduated from UCLA?

00:04:42 In 1939.

00:04:43 1939.

00:04:45 So you started really in 1930.

00:04:48 Pardon me, I'm sorry.

00:04:49 I started UCLA in 1939, graduated in February of 1943.

00:04:54 Okay.

00:04:55 And from there, you went to the Manhattan Project.

00:04:57 Right.

00:04:58 How did that come about?

00:04:59 Well, one of the profs that I had enormous respect for

00:05:04 was named Saul Winstein at UCLA,

00:05:08 and he had been a co-student with Glenn Seaborg,

00:05:14 and Glenn was trying to get promising young people

00:05:18 to come up and work on the Manhattan Project.

00:05:21 And so Winstein more or less recruited me

00:05:25 to the Manhattan Project,

00:05:26 but he couldn't tell me anything about it.

00:05:28 The only thing he could say was,

00:05:29 it's important work, but I can't say any more than that.

00:05:32 And that was when I heard the name Glenn Seaborg again,

00:05:35 because now I was to work for Glenn Seaborg,

00:05:37 but I still had no idea what he did or who he was.

00:05:41 And so I finally decided that the chance to work at Berkeley

00:05:47 on what seemed to be an important project

00:05:50 was worth the lowest salary I got offered in any job offer.

00:05:54 So you moved to Berkeley.

00:05:56 Right.

00:05:57 And what was Berkeley like at that time,

00:05:59 and what did you do your first year here?

00:06:03 The first three months, I learned later,

00:06:07 were associated with an FBI check

00:06:10 before they could tell me anything

00:06:14 about what the project was all about.

00:06:16 And so I worked for three months learning new lab techniques

00:06:20 that were appropriate to what I was going to do,

00:06:22 but with no idea whatsoever what I was doing.

00:06:25 And I found that very frustrating,

00:06:27 and so I got myself a weekend job

00:06:32 on the graveyard shift

00:06:34 in the Moore Dry Dock Company down here in Oakland

00:06:39 as a boilermaker's helper.

00:06:41 So at least I'd feel I was helping build ships or something, you know.

00:06:45 And then after three months,

00:06:47 Wendell Lattimer, who was the head of the project,

00:06:49 called me in and told me and two other youngsters,

00:06:52 young fellows who had started at the same time,

00:06:55 who were working on plutonium and neptunium

00:06:59 and what it was for and so on,

00:07:01 and that it was extremely important

00:07:03 that we get there before the Germans did.

00:07:06 And so I quit my boilermaker's helper's job that next weekend.

00:07:11 Of course, the next nine months,

00:07:14 it became more and more clear

00:07:17 that we were trying to invent

00:07:20 a new and better way of killing people.

00:07:23 And I don't know the extent to which

00:07:26 my father's remark influenced me,

00:07:29 but in any event, during that time,

00:07:31 I grappled with this problem

00:07:35 of whether I was interested in doing creative work

00:07:39 to develop an atomic bomb.

00:07:42 And after just 12 months,

00:07:46 three months plus the nine months after I knew what I was doing,

00:07:49 I went into Lattimer's office and told him

00:07:51 that I didn't want to work on the bomb.

00:07:53 I was going to quit and join the military services

00:07:57 in the most active job I could find,

00:08:00 where I stood the best chance of making a tiny help

00:08:03 toward ending the war before the bomb got there.

00:08:06 I was offered a job at General Electric Company

00:08:09 at what seemed an enormous salary at the time.

00:08:12 And they had a very good, very fine research lab,

00:08:17 so that was very enticing to me.

00:08:20 However, Lattimer felt that I should get an academic job.

00:08:26 And to give me a holding pattern,

00:08:29 while I continued to look for an academic job,

00:08:32 they hired me as an instructor.

00:08:36 Incidentally, specifically at a time when Joel Hildebrand

00:08:40 was the dean while Lattimer was away or something.

00:08:44 And Joel Hildebrand is one of the profs

00:08:48 who had a tremendous influence on me.

00:08:51 He was a bona fide researcher,

00:08:55 very interested in his own fundamental research.

00:08:59 But he, more than anybody else in the faculty,

00:09:02 was devoted to undergraduate teaching.

00:09:04 He taught freshman chemistry.

00:09:06 And I really got my beginning in teaching undergraduates

00:09:12 with Joel Hildebrand.

00:09:14 So in a sense, you decided that you would prefer

00:09:18 having an academic career and a career in industry

00:09:22 where you might eventually make a great deal more money.

00:09:25 Yeah.

00:09:26 I was strongly tempted because the General Electric Lab

00:09:30 had such a good reputation as a research lab.

00:09:33 And of course, it was more money.

00:09:35 But in the last analysis,

00:09:38 the instructorship at Berkeley was very appealing to me.

00:09:43 And after two years, they put me in a tenure track assistant prof job.

00:09:49 You were quite well known for several areas,

00:09:52 two in particular, of research in Berkeley in the 1950s.

00:09:56 Do you want to first talk a little bit about the hydrogen bond?

00:09:59 Yes.

00:10:00 The hydrogen bond turns out to be one of the most important bonds

00:10:04 in biological systems of any,

00:10:07 including the carbon-carbon bond.

00:10:09 And so this has been a very important field.

00:10:13 At the same time, I was studying flames.

00:10:17 Pitzer's work had tended to lead me to think about molecules

00:10:23 that had unusual chemical bonding.

00:10:26 They didn't fall into the normal pattern of chemical bonding.

00:10:30 And one finds this sort of species, so-called free radicals,

00:10:35 abundant in flames.

00:10:37 So I started trying to do infrared spectroscopy of flames.

00:10:41 This was very frustrating

00:10:43 because we couldn't get the concentrations high enough

00:10:47 to get characteristic absorptions of them.

00:10:51 And one day, with a postdoctoral student of mine, Eric Whittle,

00:10:56 sitting at a bagged lunch at my office,

00:10:59 I came up with this idea that maybe the thing for us to do

00:11:03 was try to trap these transient species,

00:11:06 very short lifetime, microsecond lifetime,

00:11:09 in solid inert gas at cryogenic temperatures.

00:11:14 If we could trap them,

00:11:16 then they'd have an environment that was totally inert,

00:11:19 and we could do leisurely spectroscopic study.

00:11:22 That was the so-called matrix isolation technique.

00:11:26 The key area of your research dealt with chemical lasers.

00:11:30 Do you want to talk about that?

00:11:32 Yes.

00:11:33 What we did was make a shot at it

00:11:36 by a technique that was just off the beaten track

00:11:40 and that people felt didn't have much chance.

00:11:43 That was to look for chemical lasing,

00:11:47 chemically pumped lasing in the infrared region.

00:11:50 Of course, we were geared up to do infrared spectroscopy.

00:11:53 And also, we were geared up to do it on a short timescale.

00:11:57 So we did an experiment nobody else was doing,

00:12:00 and after about maybe nine months to a year

00:12:06 of very frustrating failures,

00:12:09 we finally recognized that we were getting lasing action,

00:12:13 and that was the birth of the first chemical laser.

00:12:16 And we went on from that

00:12:18 and discovered about the first 20 or so chemical lasers,

00:12:22 all in the infrared.

00:12:24 We've been talking about the rapid scan technique and chemical lasers.

00:12:28 That brings to mind the development of the Mariner spectrometer

00:12:33 with which we attempted to learn about the atmosphere of Mars,

00:12:37 the search for life on Mars.

00:12:40 The beginnings of this project were of rather interesting flavor.

00:12:46 While I was in the Navy, at Office of Naval Research,

00:12:50 my immediate boss was a chemist, again,

00:12:54 who'd been relabeled a nuclear physicist by the Navy,

00:12:58 and his name was Erner Liddell.

00:13:01 And Erner had, as a chemist,

00:13:04 done some of the very early infrared spectroscopy.

00:13:07 So at the time, I had no idea I was going to end up working in infrared spectroscopy.

00:13:12 So now, many years later,

00:13:16 Erner had moved from the Office of Naval Research over to NASA.

00:13:21 And on some sort of an official visit, he came out to Berkeley.

00:13:26 So I asked him to come to the lab and see my rapid scan spectrometer.

00:13:30 And as he left, he said,

00:13:33 look, if you can take an infrared spectrum in a millionth of a second,

00:13:37 you ought to be able to tell us how to take an infrared spectrum of the atmosphere of Mars.

00:13:41 And I thought that was an interesting thought,

00:13:46 but wasn't quite sure how to do it.

00:13:49 A couple of weeks later, I was on a plane coming back from Washington, D.C.,

00:13:54 and I decided to spend the ride back trying to figure out how I would do it.

00:13:59 And I came up with a rather novel infrared spectrometer

00:14:04 of a type that was not yet in use, not discovered,

00:14:09 in which instead of using a dispersive element like a prism or a grating,

00:14:14 he attempted to use an interference filter that was, as I used to call it, wedged,

00:14:19 so that as you moved this interference filter in front of the detector,

00:14:23 you changed the range of the infrared light that struck the detector.

00:14:28 This simplified the spectrometer very, very much,

00:14:31 making it compatible with the idea that there would be only 25 pounds

00:14:36 associated with the whole infrared spectrometer.

00:14:39 Taking infrared spectra under conditions no one had ever taken in a laboratory

00:14:43 with no such restrictions whatsoever.

00:14:46 In any event, the experiment turned out to work beautifully.

00:14:50 The spectrometer had about a 10-inch F1 lens to look at the planet,

00:14:57 and it was a flyby.

00:14:59 We went by at about 10,000 miles nearest approach

00:15:04 and took continuous spectra every 10 seconds through the infrared,

00:15:09 looking at the light emitted from the surface of the planet,

00:15:14 which was tantamount to using as a heat source in a spectrometer a piece of ice,

00:15:19 because that was the surface temperature.

00:15:23 The experiment was able to give us a very good reading

00:15:28 on what was in the atmosphere of Mars and what was not in the atmosphere of Mars.

00:15:34 Turning to the ChemStudy project,

00:15:37 which of course was a high school educational project

00:15:41 to develop curricular materials,

00:15:44 in the wake of the Sputnik in the first instance

00:15:48 and the physicists' development of what was called the PSSC course in physics

00:15:54 to upgrade science education

00:15:57 so that we wouldn't fall further behind the Russians in space effort,

00:16:03 I had been teaching freshman chem,

00:16:06 so I had a very great interest in the chemistry preparation

00:16:09 of the students coming into the class.

00:16:11 I felt very, very discouraged about the high school education they were getting.

00:16:16 It was literally no better, no more improved, no more modern

00:16:20 than the high school chemistry course I had had decades earlier.

00:16:24 What happened next was that we were doing this on a breakneck schedule.

00:16:30 This was in the spring that we made this agreement.

00:16:33 We selected the co-authors who were ten of the leading

00:16:39 lower division chemistry teachers at the top universities

00:16:44 and ten of the best high school teachers we could get

00:16:47 from the point of view of contributing as authors.

00:16:50 We brought them together for six weeks down at Harvey Mudd College in Claremont

00:16:55 and we all lived in residence there in a dormitory

00:16:58 and worked very, very intensively, you know, like 14 hours a day

00:17:02 on that book for six weeks.

00:17:05 So I brought it back and worked alone with one of the high school teachers up here

00:17:11 for the next six weeks trying to bring it into a unified, coherent textbook.

00:17:18 As it turned out, we got a third of the textbook ready

00:17:22 for the beginning of the semester

00:17:24 and the other two-thirds came along at the appropriate time.

00:17:27 We didn't miss a deadline and no classroom was ever without a textbook,

00:17:32 but it was a real tour de force.

00:17:35 There are many interesting anecdotes to tell about this time.

00:17:41 It was, of course, a feverish activity on the part of all of us.

00:17:46 Though I carried the ball through the semester,

00:17:49 I was meeting with a group of about ten teachers in the Bay Area

00:17:53 who were teaching with the material as we turned it up,

00:17:57 and we'd meet with them once a week.

00:17:59 Now we, in this case, turned out to be this co-author of mine

00:18:02 on the Hydrogen Bond book, Aubrey McClellan,

00:18:05 who had come back to Berkeley to work at Sheppard Research Labs,

00:18:09 and I enlisted him to be the editor of the teacher's guide.

00:18:13 So the two of us would meet once a week with these teachers

00:18:16 and find out what had happened during the last week.

00:18:20 We told them what was going to happen or we hoped would happen the next week

00:18:24 and tried to prepare them for it.

00:18:26 This was an exciting time for them,

00:18:29 and for many of them just a memorable experience.

00:18:33 I have had people come back, you know, as recently as this last year,

00:18:40 but continually over the decades telling me, high school teachers telling me,

00:18:45 that was the most exciting thing that ever had happened to them in their teaching career.

00:18:50 Let's move to the National Science Foundation now.

00:18:55 At the time, you'd just spent three years serving on the National Academy of Science panel

00:18:59 on atmospheric chemistry, leading to the 76th report on halocarbons and the ozone layer,

00:19:06 and the National Academy of Science committee on science and public policy.

00:19:12 You spent a lot of time in Washington during that.

00:19:14 Yes, I did. I was also on a committee called the Lunar and Planetary Missions Board,

00:19:19 which was a group of so-called experts across all the disciplines that NASA put together

00:19:26 to advise them on optimizing the science that came from the lunar landings.

00:19:33 So that was another reason I was in Washington a lot.

00:19:36 But what really got me into the NSF job was something local here at Berkeley.

00:19:44 Some of my poli-sci colleagues decided to run a cross-disciplinary seminar on science policy,

00:19:53 how it's made and how it should be made.

00:19:56 And they got engineers and me as a chemist in,

00:20:00 and we'd have biweekly meetings of this cross-disciplinary group

00:20:06 in which we'd talk about the various kinds of science policy decisions

00:20:11 the country and the world was faced with and the mechanisms by which they were addressed.

00:20:17 About that time, I became so concerned that there were so few scientists involved

00:20:24 in Washington, D.C. in making these policy decisions

00:20:28 that I began to make it a flag that I was carrying that more scientists had to go to Washington.

00:20:35 And as a result of these activities you've mentioned,

00:20:39 my name was known in Washington and I was offered this job as deputy director.

00:20:43 And I felt if I didn't take the job, I'd have to put up or shut up,

00:20:46 and I couldn't see myself shutting up.

00:20:48 So I decided to take the job at MSF as deputy director of the National Science Foundation.

00:20:53 So you were there during the Carter administration?

00:20:56 Yes, 1977 to 1980.

00:20:58 So you came back from Washington in July of 1980

00:21:02 as director of the Laboratory of Chemical Biodynamics at the Lawrence Berkeley Lab.

00:21:08 What kind of research did you provide over there?

00:21:11 This is one of the earliest cross-disciplinary labs in the country.

00:21:17 It originated by Melvin Calvin, whom we mentioned before.

00:21:22 Melvin foresaw the importance in the biological area of having a cross-disciplinary approach.

00:21:31 And so that was one of my first aims,

00:21:34 was to make sure that I maintained that cross-disciplinary quality.

00:21:39 At the same time, I wanted to introduce some new themes and new directions.

00:21:45 And I picked two.

00:21:48 One was to broaden the traditional meaning of photosynthesis

00:21:53 from what Melvin had made it mean, which was natural photosynthesis,

00:21:58 to photosynthesis, or what I called photon conversion,

00:22:03 for the storage of solar energy, including natural photosynthesis,

00:22:08 but also including artificial systems that would do the job perhaps more efficiently.

00:22:15 So that was one aim.

00:22:18 And to bring in the modern laser spectroscopic techniques.

00:22:22 The other was to move our biological side toward the bioengineering.

00:22:28 Very obviously a coming thing.

00:22:32 And in both of these I was reasonably successful.

00:22:37 As a result of all the experience with flash photolysis and the rapid scan spectrometer

00:22:44 and the matrix isolation work, I developed a continued interest in photochemistry.

00:22:51 And so I decided that, of course, photochemistry is what photosynthesis is all about.

00:22:57 And what we needed to know was more about the chemistry

00:23:02 of a molecule after it had absorbed light.

00:23:06 This being very different from the chemistry of the ground state.

00:23:10 And so I've devoted myself to my research group

00:23:14 to the study of electronically excited molecules,

00:23:18 that is molecules that have absorbed light,

00:23:21 and how their chemistry is unique and different from that of normal molecules.

00:23:27 After I'd been back a year or two, back from Washington,

00:23:33 there was the general move to see if we couldn't find some ways,

00:23:39 some mechanisms by which the public and Congress could be awakened

00:23:45 to the importance and the positive sense of chemistry in modern industrial societies.

00:23:51 And the question was raised as to whether we should have a report about,

00:23:58 so to speak, opportunities in chemistry, which turned out to be the title of our book,

00:24:03 that surveyed what chemistry is all about in the modern world

00:24:08 in a way that would persuade people that it's much more important to them

00:24:13 than is merely indicated by saying that,

00:24:15 look at all the chemicals in the environment that are being spewed up there and killing us all.

00:24:21 The National Academy drew together a group of people

00:24:27 and asked me to chair it to decide whether such a report was needed.

00:24:32 And just at the time that we had our first meeting,

00:24:36 a move was made to have briefings to the present science advisor

00:24:42 on six of the most promising scientific areas

00:24:47 for special emphasis by the administration,

00:24:51 this under Jay Keyworth as present science advisor under Reagan.

00:24:55 And to my irritation, chemistry wasn't even considered.

00:25:00 And I decided right then that that means we've got to have this report.

00:25:05 So this group came to the unanimous agreement there should be such a report,

00:25:10 and then the question was who should edit the thing.

00:25:13 And of course I had the experience with chem study

00:25:15 and I was all full of fire about this issue of chemistry not being well treated

00:25:22 as a result of my experience in Washington at NSF.

00:25:26 So they asked me to be the editor of the book.

00:25:30 With these preeminent people on the committee,

00:25:34 we were able to go out to the science community, the chemistry community,

00:25:38 and get the leading experts in any particular specialty we wanted

00:25:44 to write essays about what was going on in their field.

00:25:48 And some 300 scientists responded with such essays.

00:25:54 And from that then this committee and I tried to generate a book

00:25:59 that you could lift in the first instance,

00:26:02 and that had language level and coherence

00:26:05 so that it could be read by science policy people in Washington, D.C.

00:26:10 And that was the Opportunities in Chemistry,

00:26:14 as you say popularly called the Pimentel Report.

00:26:18 One of your initiatives as president of the American Chemical Society in 1986

00:26:23 was to promote the public understanding of science.

00:26:27 Is the ASC doing enough about this?

00:26:31 The ACS, yes.

00:26:34 They're working very hard at it,

00:26:37 and I think doing a fairly good job.

00:26:41 One of my initiatives was to originate the concept of National Chemistry Day,

00:26:48 which was a day to be celebrated, so to speak,

00:26:53 across the country by all of the local sections,

00:26:57 of which there are 130 in the American Chemical Society.

00:27:01 The idea was to try to reach out to as many people as possible

00:27:05 to tell them about chemistry,

00:27:07 what it's all about, how important it is in their lives in a positive sense,

00:27:13 and to provide an opportunity for the chemical industry

00:27:18 to reach out toward the public

00:27:21 and let them know that the chemical industry cares an awful lot about safety,

00:27:25 toxic materials, and the welfare of the public

00:27:30 in a bigger sense than just selling more products.

00:27:34 You obviously had a lot of fun in chemistry.

00:27:37 You bet.

00:27:38 I feel that one of the luckiest decisions I made ever,

00:27:42 for what I now consider to be a rather wrong reason,

00:27:45 was when I decided to go into chemistry.

00:27:48 A very exciting field,

00:27:50 and I've never looked back with any kind of regret.

00:27:55 We are at a moment when chemistry is benefiting from enormous opportunities

00:28:02 associated with new instrumental developments.

00:28:06 One of the easy things to point to is the laser,

00:28:09 which has gotten us down to a millionth of a millionth of a second,

00:28:13 picosecond timescale,

00:28:15 and that means that any chemical phenomenon that you can mention

00:28:19 can be now looked at in real time.

00:28:22 This means that questions are being posed and answered today

00:28:25 that you just wouldn't think of answering,

00:28:27 even posing some decades ago.

00:28:30 But can the young George Pimentel of today have as much fun as you had?

00:28:36 Oh, I'm sure.

00:28:37 See, as I say, I think what science is all about is giving rain,

00:28:42 open rain to individualism and creativity,

00:28:47 and chemistry is as good a place as any to do it.

00:28:51 Kelly, thank you very much.

00:28:52 Good luck.

00:28:53 It's a pleasure.