Dudley R. Herschbach
Interview with the 1986 Nobel Laureate in Chemistry, Dudley R. Herschbach, March 2009. The interviewer is Adam Smith, Editor-in-Chief of Nobelprize.org.
Dudley Herschbach recalls growing up in rural California and the National Geographic article that sparked his interest in science, the academic scholarship that led him to Stanford and the philosophy of education he learned there, the adventure in pursuing scientific research and why it is congenial to the human spirit (15:58), the “lunatic fringe area” of chemistry for which he would later be awarded the Nobel Prize (27:01), what it means to teach science as a liberal art and the mentors who inspired him (40:46), and, finally, the fascinating evolution of molecular engineering within the discipline of chemistry (51:59).
Dudley Herschbach, we are sitting here in your office in the chemistry department at Harvard, where you’ve been since 1963 when you became professor here.
Dudley Herschbach: Yes, although I was here earlier as a graduate student as well, I got here in 1955 as a graduate student.
Exactly, you’re part of the fabric of the place and indeed your wife is as well, she’s also a …
Dudley Herschbach: Yes, she was a graduate student that I met when I came back in 1963.
Your childhood was spent in a very different environment and that’s where I’d like to begin. You were brought up in rural California in what is now …
Dudley Herschbach: Then rural, yes.
Exactly. Now part of Silicon Valley.
Dudley Herschbach: Exactly. I was born in San Jose when it was a town of 20,000 and it’s now, I think, 1.4 million or so. Santa Clara valley was all orchard essentially, Cupertino, which now is indistinguishable from downtown Los Angeles then was where two two-lane roads crossed in the orchards. There was nothing within a mile or two of that intersection in any direction, just a general store at the intersection with a solitary gas pump out in front, the scene that you might see now on a Western movie, so it changed totally in the span of a few years in the late fifties, early sixties when Silicon Valley burst for us.
That was the backdrop to you somehow developing an interest in science as a child. Where did that come from?
Dudley Herschbach: Actually, I can tell you very specifically. I just had my 11th birthday and we were visiting my grandmother who lived, like we did, near the edge of San Jose. I always enjoyed going there because she had a National Geographic magazine, which of course was filled with beautiful photographs and all. This one had an article on the heavens above by Donald H. Menzel, Harvard college observatory ‒ this is way out in San Jose, California. It was certainly the first time I heard of Harvard and I wasn’t even aware of hearing it, but then of course … but had these gorgeous star maps with the mythological figures for the consolation super bowls, I fell in love with them. My grandmother gave me that issue because she saw how much I was taken with it, and I started making my own star maps and reading about astronomy and climbing up a tree we had in the backyard at night and I had a flashlight, it just clicked briefly, I didn’t want to light adapt my eyes, picking out the pattern I made and print pick the paper with patterns of the constellations. It just fascinated me.
The rural environment was presumably good for star watching as well.
Dudley Herschbach: Yes, indeed. There are lots of stars at night because it’s not so many lights as you now have in city environment.
Was there an appropriate sort of structure to foster this interest, this burgeoning interest in science then?
Dudley Herschbach: Well, it was fostered. I was then in a little four room school, two grades per school. My graduating class from that grammar school was 11 kids, but there was a bookcase about this wide, about this high, and it had a couple of books, as my teacher pointed out, about the planets and all. Those were the first scientific things I read. Then of course our town had a little library and I began reading things there and I just got more and more interested in science. By the time I went to high school, of course I was interested in taking science courses and all, but even then, I wasn’t even thinking of going to college yet for people of my vintage and that social category it was not something you expected to do. But I was a good athlete and my coaches would say, “Of course you’re going to college”. Then my teachers began saying the same thing because I was a very good student, so then I began to realize, oh, I guess maybe I’ll try college.
But the original impetus to come to go to college was coming from the sports side, a sports scholarship?
Dudley Herschbach: It was, yes. I was quite a good football player, American football, and in fact, when it came to applying to college, I got many telegrams, congratulating me on being admitted to colleges and universities I hadn’t applied to at all. I had not applied to them, but the football coaches would get their admissions committee to accept a student who hasn’t applied.
You were a hot property at that point?
Dudley Herschbach: Well, any rate, I was offered several athletic scholarships, but back then, at least at Stanford where I went, the academic scholarship I was offered was more valuable than the athletic one, so naturally I took that. Now I doubt it’s true anymore, sad to say.
I think priorities may have shifted somewhat.
Dudley Herschbach: Yes, and I did play football, but I quit after spring practice in my freshman year because all of a sudden they changed the rules. Now they allowed unlimited substitution and we’re copying the pros. It used to be ‒ people have forgotten ‒ used to be that you couldn’t substitute at all in American football, in college, except for an injured player or a punter that was allowed.
What’s a punter?
Dudley Herschbach: A punter is on fourth down. You have to kick the ball down the field or you risk … If you don’t make your first down of enough yardage, the other team takes over, so usually they punt. I didn’t like that because suddenly in spring practice they had all these other coaches telling us what to do. Whereas before the game really belonged to the players, that was a whole philosophy, coaches weren’t allowed to signal in plays from the sidelines, anything, it’s completely the opposite of what it is today, and so I said, “Well, hell, I don’t want to play that way”. Today it would be different if you have some talent to do well in a sport like football, you’d have to do it at least because as a decent player you get millions of dollars a year as a rookie, even in the pros.
In some ways it’s fortunate for science and perhaps for you that they changed the rules at that exact moment.
Dudley Herschbach: I wouldn’t have wanted to make it professional anyway, but I discovered then that college was a much more exciting playground than the football field in any case, because it opened my eyes. I was so ignorant when I went to college. I couldn’t imagine all the fantastic things.
I wanted to ask you about that because if nobody in the family had been to college before, presumably you didn’t have that much idea of what you were going to step into.
Dudley Herschbach: I thought it was something like high school, at a little higher level. My parents had heard of people who had gone to college, and they had a very dim view of it. They thought that college had a lot of these egghead professors with funny, unrealistic ideas. Then the students were rather arrogant because they’d been to college, so they were then too proud to work with their own hands. Those are the very words that my father used in particular. Of course they were right, but only partly right. If I met so many wonderful professors who had ideas well beyond the egghead category, and I came to appreciate that ideas were among the most practical, valuable things. They were right ‒ a completely different view.
You were taken very early on by the idea of reaction kinetics and the field grabbed you. What was it that you found so appealing?
Dudley Herschbach: My freshman advisor was a young chemist that really I owe to the fact that in high school, the most outstanding teacher I encountered was in chemistry, even though chemistry, when I first encountered it in high school, mystified me. Anything else I started, it seemed obvious right away with the general idea the subject was and all, but chemistry looked to me a hopeless hotchpotch of odds and ends. It took a while before I began to get a feeling for it. I now, after years and years, have a way of explaining why I think a similar reaction with many people when they meet it in high school or college, you can come to that later if you like …
I would love to come to that.
Dudley Herschbach: … but Mr. Meischke, who had a master’s degree from Berkeley, was a fabulous teacher, and anyone who took his course learned a lot of chemistry. I didn’t find out how good it was until I took a college course, and it was such a breeze after Mr. Meischke’s course, so I must have put down chemistry as a possible major when I applied to Stanford. Although I, at that time, was not sure at all. I knew I was interested in science and math, but I didn’t know that I would become professional in it at that point. I think that’s why I was assigned Harold Johnston as my undergraduate advisor. There’s a picture of Harold Johnston as he was when he was a young faculty member at Stanford, my advisor. I remember the very first meeting with half a dozen or so of his advisees, all freshmen, why he explained to us about a university, he said that it’s a place to preserve knowledge, that was obvious libraries, and all to transmit knowledge.
Well, that was a teaching function and to create knowledge, to me, that was a totally new idea. I had no notion that such a thing went on in what I presumed was just a sort of high-level high school. He went on to explain his own field was the field of chemical kinetics, which has to do with how fast chemical reactions take place to change one kind of molecule into another. As he described it, it sounded a very heroic enterprise because typically there are many reactions steps. It is the molecular level, many kinds of steps involving different molecular interactions and rearrangements, to add up to the overall reaction that you can observe in the methods that were available then, which in deal with bulk, zillions of these little critters doing their thing, and the chemist guess what’s happening at the molecular level, they are very crude ways to test those steps.
At any rate, he would explain that their so-called mechanism, a list of the molecular steps that were thought to be involved, was always provisional, because if someone realized there was some intermediate species that hadn’t been recognized before, you might have to revise the whole thing and so on. That’s what the first impression was. By the time I was a senior, I learned a lot more about all this and learned how hard it was. I had in a physics class a professor makes an offhand remark that acquainted me with this method of molecular beams. I said, “Gee, that’s the way one should study chemical reactions”. You could find out what happened in the individual collisions of molecules. When I went back and told Hal about that, he laughed and said, “Well, of course,” but not in enough intensity. That was the very beginning.
Even when you were an undergraduate, you’d seeded the question, you were going to go off and answer?
Dudley Herschbach: It’s actually true. It really started that. I wanted to find out what happened at the molecular level. You rearrange these bonds and all.
Then you took time during your graduate work to equip yourself with the right tools.
Dudley Herschbach: That’s what I wanted to. I wanted to learn more about the forces involved in molecules and how they rotated and vibrated and the atoms within, and also I deliberately chose from the reading I’d done to come to Harvard and work with Bright Wilson who was a great, great mentor and a real architect of understanding the molecular dynamics of stable molecules. So that was, I regard as a precursor to studying the molecular dynamics of rearranging bonds.
That’s an interesting word to choose as a description for Bright Wilson ‒ an architect of understanding. Do you mean by that, that he was able to pull all the pieces together to create a framework for understanding?
Dudley Herschbach: I’ve often said that people think science is essentially a technical thing. I think the kind of science we’re talking about is better described as architectural. An architect has to understand quite a few technical things, but not in the same way that the engineer or the building contractor needs to. Those technical things are not actually the essence of architecture. The way I think of an architect is someone who recognizes that at a particular time, the building materials and methods available allows them to create space in a way that’s shaped to not only be the practical sense, effective, structure to carry out its purpose, but it conveys something beyond that, that inspires people to realize that it opens their eyes to new possibilities that you didn’t anticipate would be there. That’s what really frontier science is like, it’s a human enterprise.
Often the exact content, I think, is not very important compared with how it inspires other people. I’ve often said that it’s the spiritual content of an experiment or theory that has the greatest impact, because science depends on how other people respond to it, just as in art. I think you value a great piece of art or a performance because in some way, having witnessed it, it changes how you think, how you react or what you do next. It is exactly the same in a fine work of science that the people who come in contact with it, they are after thinking in a different way. They probably do something different in their own work often and so on. Most people think, Oh, it’s just some technical thing and you do this or that, but there’s much more to it than that.
It’s an extremely appealing notion that if people saw it that way, it really would change public perception of science.
Dudley Herschbach: I wish that were so because to me, science is an adventure of our species and it ought to belong to everybody. It is so sad that in the 21st century, a very large fraction of the world’s population, even in a country like the US has hardly any inkling of what is really going on, their understanding of much of science is not hardly beyond the medieval era. It was really true, sad to say, their encounter in school with science, seems, I think, to many people ritualistic. They don’t really understand why they are subjected to taking some of this science or math because they have the impression that ordinary people can’t be expected to understand this or parents don’t seem to know or care much about it. Our teachers feel uncomfortable with it in high school, say largely, and it’s so darn sad. I, in my own domain, do what I can to change people’s way of thinking about it.
It’s also so strange that this should happen because people start out as children, as little, little scientists, busy exploring.
Dudley Herschbach: I often say every child is born a scientist and an artist – they are so curious and they have the urge for self-expression. Then in school, this is quenched, except for a small fraction of so recalcitrant that they survive anyway, becomes scientists, stay scientists and artists and develop into it. Why is it quenched? I think often, especially in the US, it’s so clear that ‒ many students have told me this, who have later avoided science ‒ that science and math were the first things encountered in school where there seemed to be only one right answer, and you were expected to see how to get the answer by some approved procedure. If you didn’t see this right away, of course you’re likely to be alienated and turn away from it. It’s a self-protecting mechanism in our species, and the sad thing is how different that is than real science, because I like to say, in frontier science, the researcher, like the neophyte is confused much of the time. The difference is the neophyte is upset often to be confused: I don’t understand this. The researcher is very pleased to be confused because if you’re not confused, if it’s all clear right away, that means there’s no chance you’re going to uncover something that’s not already clearer to people in the field. You want to make a value and add contribution to your field. That means being confused, that means there’s something there that probably other people don’t understand either. And so, “gold in them thar hills” in that direction. The veteran scientist also appreciates something that I preach a lot about because the general public and people /- – -/ through school get the wrong idea. Science is extremely congenial to the human spirit.
It’s much easier than almost all other human enterprises. Why? Well, think of business, sports, politics, sadly war. You may think of a very, very well grounded, sensible wise move, but you know what? During the time it takes to organize things and start implementing it, the situation has changed and may turn out to be a fiasco instead of a triumph. You read about such things in the paper every single day, but in science, what you’re after ‒ call it truth or understanding ‒ waits patiently for you. It doesn’t change. So you can miss it, misunderstand what you’re really after or you dimly begin to, after a while, appreciate what you should really be focusing on, all that, and yet waiting for you, your chance to find it. That’s why science makes so much progress. It is not because scientists are more smart than other people it’s because they don’t have to be, that’s the real reason.
If more people understood this, especially students, and were taught in such a way that they understood this, they’d see the different light altogether. I love to say, to be a scientist is something like being a musician, a real musician, not just a guy who turns up the knob, you need to master your instrument. You need to master the literature, in music and the culture and science is much like that. But compared with a musician, the scientists can, and probably will, play 99.9% of the notes wrong, then get one right, and be appropriately applauded for getting one right at last. It’s really true. It’s really true.
Exact opposite to being a musician who has to get it right, a hundred percent.
Dudley Herschbach: Yes, I’m odd by the musician. I’ve gone to many concerts and I’m an amateur musician. Other people will say, “Good performance, but gee, at the beginning of the second movement he was way off in that B flat.” One note of all the zillions of notes. Not perfect, but in science you play most of the notes perhaps pretty far off. But it doesn’t matter if you know and then get the right one. Do you see what I mean? This is not appreciated by the general public.
Why would one do anything else in life if you’ve got the chance to be wrong all the time?
Dudley Herschbach: Maybe it’s a temperamental thing. I often say to students that, what you want to find out as a student is some domain which appeals to you temperamentally as well as in terms of what seemed to be your special talents. That’s part of what the student needs to discover, by exploring different areas and all. What you want to try to achieve in your education is competence in some area and confidence. You need both those things and you want them in appropriate measures. If your level of confidence is much higher than your level of competence, that doesn’t work out well and vice versa.
The confidence thing is perhaps difficult to understand when one puts it in the way that you just have, that you are mostly getting it wrong. You’re mostly not uncovering the truth, you’re missing the mark. You need to be fairly sure that there’s success somewhere down the line, just to keep going.
Dudley Herschbach: That’s right. You’d have to have a high threshold for frustration, and you can cope with that. Because over the many, many years that I’ve worked with students … I really think of myself as primarily a teacher, but that’s one of the joys of the scientific career I’ve had, working with students and seeing how they flower and develop. It’s a beautiful thing, so many friendships, last the life and all, but I try to emphasize to them how science is such enormously broad domain. They’re different realms that are congenial for people with very different temperaments and talents and all the rest. Again, the many students get the impression that you have to be very good in a whole lot of domains, and if you’re going to be a scientist, math in particular ‒ that really isn’t true at all.
Not so long ago here at Harvard, there’s a big flap because the president was trying to explain why he thought not so many women would join the faculty in science, and he pointed to mathematics. The fact is most of science people don’t use much more mathematics than the grocery store clerk. They really don’t. There are domains far from that who use the highest level of math you can find, but for most of it, it’s not the case. The question of finding your niche, finding the area and then you begin to feel, Well, maybe I’m destined to pursue this. If it turns out that other people at the time, don’t think it’s all that promising or exciting, or for some reason they’re not focused on it, that’s in particular the case of Nobel Prizes. I’ve heard many, many stories from laureates themselves, or read them, about how they got into their line of work, and again and again it’s a similar story. When they started out, lots of people thought they were wasting their time, and that was certainly true in my case as well. But if you have the sense that, Ah, this just appeals to me, and it’s the kind of thing that, for reasons maybe I don’t fully understand myself, just grips me, well, okay. I’m in destined to do that. There are lots of other people who can take care of other things, I’m going to pursue this, and that helps enormously in any field of work. I think that’s true in art as well as science.
It gets you through the frustration for a start.
Dudley Herschbach: It means that the student who undertakes this, a student growing up to be a scientist, has to have a certain level of confidence, and the feeling, and that they have to have a situation in which they can do it. They can afford to gamble like this and not be too worried about whether they’ll lose their job or not get promoted or whatnot. So, you’ve got to have freedom. You’ve got to have support to really do your best work, and I’m afraid a lot of things could spiral against that in the modern world.
But it’s back to that, the question of how you chose your question, because you chose the right question at a young age, you were advised that it was a bit of a crazy question, and you just said, Never mind, I’m going to carry on.
Dudley Herschbach: Yes, that’s exactly what happened. People said, this is a lunatic frame area, and I love that name, but what I didn’t anticipate at all, when I decided that I was going to do this, even though it was, Oh, that’s too dangerous, you’re putting all your eggs in one basket, it doesn’t work, you won’t get promoted. I didn’t care. I was confident that I’d find a good enough job somewhere. This didn’t work, I just wanted to try. But what I didn’t anticipate was that thereby I attracted the very best, most ambitious graduate students because those people were not satisfied to do the sort of safe standard things that were under control. This was an enterprising thing, that was adventurous and pushing in a new direction, it was clearly appealing, because it was very fundamental to get at what happened at the molecular level, which people didn’t think it was really feasible to do. Because of that it was a self-fulfilling thing. I got these tremendous, devoted and excitable people like me to work with me as graduate students and post docs. It was such a beautiful experience over many years on, and then saw the whole field develop, in ways I couldn’t have dreamed would happen. I just wish more people could be in a situation where they could do that.
It’s a nice idea that in this network of scientists there’s an aggregation of risk takers, that you find each other and work together.
Dudley Herschbach: Yes. But as I say, there are situations now where I’m not so sure this would happen as readily as it happened in my particular time.
Do you think it would be hard to get support for the risky?
Dudley Herschbach: I think there’s no chance. If I wrote a research proposal in today’s climate that was akin or similar to what I was doing back then, that wouldn’t get funded. The whole attitude is such, you don’t find that anymore.
Why has that change taken place?
Dudley Herschbach: Partly because there are many more scientists and the whole business of proposals has changed character. Now it’s almost a commercial enterprise, what will come of this and so on. That wasn’t true way back in the late fifties, when we were talking about, when I got started as a young faculty member at Berkeley, it was okay to do something that was pretty far out blue skies.
Basic, you were looking and …
Dudley Herschbach: It might not work. Partly, the early support came from the rad lab at Berkeley, I was just lucky to be there. They had funding and they had flexibility, the fundable things. I had some special grant, Sloan foundation was one variable, a valuable one. It supports young faculty members today, too. It seems that things didn’t relatively speaking cost so much either, so it was only a few, maybe three or four years in that I began having to raise money from grants. What’s happened since, the way things have evolved is more and more essential to have to get grants. People hardly even think of undertaking work unless they have a grant to do it ‒ that wasn’t necessary at the very beginning of what I did, and that helped a lot.
Once you’d established the molecular beam approach to studying single, molecular collisions and the reaction dynamics of those, you were able to attract, Yuan Lee to your group, and you mentioned earlier the ability to attract an amazing students.
Dudley Herschbach: Yes, that’s a perfect example. He was, of course, the off scale super example.
What was so special about him? What is this about him?
Dudley Herschbach: I met you Yuan Lee when he first came to this country from Taiwan as a graduate student at Berkeley and his English still wasn’t too good. It was wonderful to see his transformation, but, as it turned out, I moved to Harvard only a year after he arrived at Berkeley as a graduate student. He really did, as he explained to me later, want to work with me, but he misunderstood when I was telling him, because my general policy was always to accept any student who wanted to work with me. I felt I had a responsibility to do that, but I wanted to be sure since it’s a very important decision for them that you talk with other faculty and think of other possibilities. I always stressed this and then if they came back another time or two, then okay, I would be willing to let them do this reckless thing and work with me. But I think because of the language thing, he didn’t quite understand any …
He thought you were sending him away?
Dudley Herschbach: Yes, well I can appreciate it now, but when he came here to post doc with me, it was now at Harvard, he actually wanted to do theory because he had as a graduate student at Berkeley, done a beautiful off scale experimental work. I knew that Yuan was something super special as an experimentalist, but he really wanted to do theory because I was known for doing both theory and experiment, but he wanted to fill out his background. But he was too shy to tell me this. When I was ranting about, Oh, Yuan, the time has come to make this jump and build us new apparatus that will allow us to go beyond this limited family of reactions we had been able to study up till that point. Of course, he went ahead and did, that was great success. There’re about a hundred machines there in the world now that are essentially like the one that Yuan led construction of when he was a postdoc here.
But he was only being polite in doing it.
Dudley Herschbach: Only 20 years later did he tell me this, that what he really wanted to do was theory. He would’ve done fine in theory too, as it was there he wound up, he probably has constructed more really groundbreaking horizon moving apparatus, certainly in the field of chemical physics, than maybe a hundred plus other people put together. I used to say he was the Mozart of chemical physics, because musicians know that Mozart was – is ‒ great and admired as a composer, not just for his ingenuity and all his creativity, but especially for how, with minimum musical material, he made so much out of it. Yuan’s design of instrumentation is a work of art in exactly that way, as well as more practical, pragmatic ways.
He had studied everything relevant to it as a graduate student already, he taught himself to do machining, to drew drawings, machining drawings and all the rest, just everything. We would discuss this apparatus that he undertook to build here. We discussed everything, there was Yuan and two first year graduate students joined him, and the four of us would meet together to discuss what we were doing. Every important question finally Yuan would deliver his verdict, “Should be all right”. Once Yuan said that we were fine, we knew we’d made the right decision and it always worked out that way. Beyond that, he’s a wonderful person and this is very valuable in science, the personality of people and how they interact with others, inspire them and all ‒ it counts for a lot. Maybe you’ve interviewed Yuan already?
I’ve met him, but never interviewed him.
Dudley Herschbach: I hope you’ll do because he’s really wonderful.
Indeed. On being a nice person, it’s not the image of the single scientist working alone, isn’t it at all? It’s community?
Dudley Herschbach: Yes, that’s right. Even the people like Einstein who are the iconic model for the lonely genius, it’s completely misleading. I’ve written a paper on Einstein as a student, who was for one of these celebrations in 2005 of his miracle year, and I looked into that pretty thoroughly and Einstein himself would say how much you owe to many other people. It’s very clear when you study his early years.
It’s funny that it’s such an appealing concept sort of to the world. We keep on talking about lonely scientists.
Dudley Herschbach: I think it’s more efficient that way, people say they like to identify one person, but really, I think most domains, if you really study it you realize that one person is representative of much, much more ‒ a whole culture or subculture that evolved in a particular historical situation. I often said prizes like the Nobel Prize shouldn’t be given to people. They should be given to atoms or molecules or ideas, but we don’t know how to do that, so instead it’s accustomed to give them to someone, some person or combinations of persons who have become identified with something that not only involves a lot of other people, but sometimes it almost seems supernatural that there are things there that we didn’t know there and we find them and then they start interacting the ideas and observation in ways that we didn’t anticipate. It almost seems like they have a life of their own and you are just lucky enough to be there, to sort of cultivate it. Just as your children are born, you have a relatively minor role, especially males, and then you discover all they have there and get to enjoy and participate and maybe fostered hopefully in the good direction. It is the same way in working with scientific things that you get into.
In some ways the recipients of the Nobel Prize are representatives of the areas that they …
Dudley Herschbach: Oh yes, I think so. The whole idea of the prizes. It seems to me it’s sort of sad, and at least in the US especially, as regardless creating every October a new batch of minor celebrities, but the real message, which I think is appreciated more in Europe, is that this little country, not very big – Sweden ‒ because of a very peculiar fellow, this Alfred Nobel, every year now for more than a century sends out this message to the world: this kind of thing is valuable for our whole civilization. It really is. That’s the real message, but it’s somehow not registered that way, in the way I think it ought to be.
I was going to ask you about students. I was going to ask you what you look for as students, but you’ve already said that you would accept anybody who shows a dedication to joining you.
Dudley Herschbach: Yes, I’ve accepted a fair number of students who were thrown out from other research groups and I just feel okay, I should do my best if the student really wants to undertake work nominally under my direction. It’s usually worked out very well. I feel okay, I did something that needed to be done
Again, it makes it sound all very easy.
Dudley Herschbach: I wouldn’t want to say it’s been always that easy, but it’s been satisfying.
Could you summarize the approach to science that you’re trying to impart to your students? What do you tell them to do? How do you encourage them to approach the questions?
My basic philosophy is that science should be thought of as part of a venture of our species just as artistic things are. I try to teach science as a liberal art. To me that means the highest aim, as I understand it, of liberal art is to bring students to the habit of self-questioning, critical thinking, not just accepting what they’re told and all the rest. Science should be a very important component of this, and it’s not generally the case for most students who go through college in the United States, at least. Even those who are studying science don’t think of it as part of liberal art education for the most part, they tend to think of mastering technical stuff. The technical stuff certainly you need, no doubt about that, and it’s very satisfying to master some part of mathematics, particularly because it’s like a language, you’re empowered. You can do things, you can compose things, you can work out things and all you could do otherwise. It’s a very satisfying thing.
You need a fluency.
Dudley Herschbach: You need to become fluent in something and you really are empowered if you can do that. But it’s adventurous. I want it to be adventurous. I think that PhD in particular should be a personal adventure where you get to explore and discover your own abilities, sharpen them, refine them. But explore some domain that’s not all mapped out by some higher authority. As my mentor, Bright Wilson, did too. I want to give a long leash, I don’t tell the students what to do exactly.
I think this is a promising direction, but here’s another. You should choose which one you think, which appeals to you. Bright Wilson wrote a book, Introduction to scientific research. It is still in print in Dover, that I’ve bought in bulk, given to many students. He describes this same kind of philosophy in his early chapters. If the student chooses to pursue a particular line, then it already begins to be something that they’ve taken ownership of. They’re not doing it. When they say,” I work for Dudley” I always say, “No, you don’t. I work for you. You’re working for science. We’re both working for science”. I always wanted that because that’s the way I felt about myself, and I was lucky enough to have wonderful mentors who had philosophical outlook that appealed to me a lot.
I really feel I’m fostering that in my own way and transmitting it to my own students. Harold Johnston, my undergraduate advisor now emeritus faculty member at Berkeley, but he was at Stanford at that time, a very distinguished scientist and a marvelous person and Bright Wilson were my PhD advisor. I was incredibly lucky to have people of that caliber and that character. I think everyone who worked with Hal, or Bright Wilson, came away with such respect for them that you wanted to emulate them to the extent you could in your own life and in dealing with your own students. You would’ve been embarrassed and ashamed to do anything that would let them down that would measure up to their standards. There are other people like Frank Westheimer. I never worked with him, but a colleague here at Harvard, he was another such person who had the same kind of impact on a student. It’s tangible. You could practically tell that must be a Westheimer student or must be a Wilson student. I think it really, at least in my eyes, it’s a very important thing.
It’s presumably the most important relationship in most scientist’s career, this beginning, this mentorship.
Dudley Herschbach: I often like to say, in dynamics, not just molecular dynamics or any kind of dynamics, there’s a force field that influences the development of the motion, but the initial conditions are always tremendously important and so it is with the careers, the dynamics of people’s careers in any field, but it’s very, very easy to trace in science often.
Turning just for a little while to the collisions themselves, they allow you to study the making and breaking of individual bonds, which is sort of the basis of everything in chemistry. Maybe it’s too broad a question, but has that ability changed the way one views chemical reactions? Because chemical reactions are certainly before this used to be viewed as a bunch of reactants giving a bunch of products and that’s what defined the reaction, but now you can see the middle stage. Has it changed the way one views?
Dudley Herschbach: Yes, I think it’s had quite an influence in the way people think, which is in the end for a long time. Chemists, as I alluded to earlier, wanted to map out these individual molecular steps, but they had no way of looking at individual steps and checking if that’s really what happened because, often you have what are called, intermediates ‒ they are so reactive. There’s a special, not very stable, combination of atoms, they’re so reactive they don’t stay around long enough to be observed by ordinary means. They’re postulated to be there maybe, and when you made deductions from what you thought the influence of that intermediate might be, you’d try to test it by varying the temperature or the concentration of reagents and seeing if things changed in a way that seemed consistent with a postulated presence of this intermediate species.
Often it didn’t agree with experiments, so you’d postulate something else. That was the way the game was played for a very long time. Of course, in addition to our ability to observe a single collision so we could see whether the step that was postulated took place more and more, you had other means to probe in particular laser techniques. Ahmed Zewail for example is a spectacular example in that he could follow reactions in time and trace them. Whereas the beam experiment is a different thing. Fundamentally, you prepare things that are on the molecular scale very far apart. They come in and interact very close together. They fly apart and you observe them and they’re far apart again. But what has happened in between is influencing the speed with which they come apart, how rapidly the molecules are tumbling, how they’re oriented in space, how fast the atoms vibrate, all those things you could observe was they’ve come apart.
But /- – -/ you didn’t have a way to follow them all the way through in time, that was a very satisfying thing. More and more techniques have come along that augmented this ability to study the individual steps and detect in particular whether there are very short-lived intermediate species reacting intermediate in all the rest, probed what’s called a transition state when they’re really close together. Chemists also now have much better ability to compute from first principles from quantum mechanics what the forces are like. We have both better ways to test that and compute it but is not yet fully under control. Chemistry is charged difficult enough and complicated enough to keep you humble. We don’t understand all that we’d like to, new things keep being discovered, even in this domain we’re talking about, but of course, many other domains and frontiers of chemistry. It’s a very rich and ongoing enterprise.
If one’s able to start defining the intermediate states, can you start to reclassify chemical reactions in terms of the intermediate states through which they go?
Dudley Herschbach: Yes, I always felt that what we needed to do and needed to aim at doing in this business of single collision, chemical reaction dynamics, was in a way to emulate what Pauling ‒ and he’s the label for this whole field of molecular structure ‒ understood in terms of electronic structure, because electrons are the key part of governing what goes on in interactions between atoms and molecule. We needed in these experimental tools to develop ways that we could connect the dynamics to the electronic structure. That’s what we were able to do in an observational way. Now theory allows you to connect it with quantum mechanics more directly, so that overall aim is being more and more approached and fulfilled along the way. It’s very satisfying to see how that works out, and every day we are getting a little bit further along,
At some point it will become a predictive tool for working.
Dudley Herschbach: Yes, in principle. It is already for some very special domains, but in principle, those will spread wider and wider in chemistry. It maybe is a good thing. I joke about we’re evolving a new species, homo computers because the computer … So many students are clearly more comfortable in front of their computer, they spend so many hours a day. It’s certainly true that more and more molecular engineering you could say is evolving in chemistry, is you master parts of it, becomes more civilized and you can compute pretty well and predict pretty well what’s going to happen, but we have a long, long way to go because great parts of chemistry are not only uncivilized, but hardly explored. I like to emphasize this. I mean, take the case of buckyball.
You’ve got an origami model of a buckyball.
Dudley Herschbach: A student made it for me from 90 pieces of identical paper, all slipped together to make this nice buckyball. It’s very lovely. The buckyball story is quite wonderful because the likelihood of having this structure was 60 carbon atoms ranged like the vertices of stitches on a soccer ball, the likelihood of this was anticipated, but not generally paid much attention to. Years before it was recognized and found experimentally, even though it’s a form of carbon for Pete’s sake, buckyball must have been in the ashes of caveman fires and so on too, that just wasn’t discovered to be there. It’s a very stable molecule, so you say how come it wasn’t discovered before? Even a serious, very, very capable organic chemist undertook years before it was discovered to synthesize buckyball and didn’t succeed.
It was discovered in the molecular beam experiment. The reason is that in the molecular beam experiment, you were very far from some dynamic equilibrium. It seems that the pathway that you could get there, by a route that’s far away from equilibrium, whereas if you did an ordinary chemical environment where you have bulk interaction all the time, you can’t get terribly far away from equilibrium because there’s so many collisions keeping it sort of steady and so on, not very far away. This is just one example illustrates how much more chemistry is to be found by pathways we’re not aware of because most of the chemistry is done and biochemistry too, so close to equilibrium. We’re working, as I see it, around the fringes and this lunatic fringe part, which in particular the molecular beam business allows to get far away from equilibrium, is still who knows how much more is out there, but there must be much more that you can find far from equilibrium than near equilibrium just seems to reason that’s the chance.
There’s far more to do, and of course this buckyball thing is a nice example. That was just found out of curiosity. Why you get this big bump in the mass spectrum when you run a lot of carbon vapor in a certain way? That proved so intrigued, so appealing aesthetically, that it touched off this whole field of nano chemistry, huge. People looked into more and more things that has discovered the nanotubes. Now this graphene, the single layer of sort of graphite, which is the most common form of carbon, now you have a single layer of this stuff and it has these almost magical properties of fantastic conductivity and other properties. All of this is connected. One thing stimulated another, and even though graphene is far away from beam expansion into a high vacuum and all that, it’s clear that there is this direct connection.
Now those new areas are talking about are labeled commonly as nanoscience.
Dudley Herschbach: Nanoscience. Now they’re part of material science.
Yes, and yet fundamentally they’re also chemistry. I wanted to come to this question of chemistry’s unpopularity that people seem to want to rebrand it as something else.
Dudley Herschbach: There’s this famous little cartoon of the little girl looking up to her mother in the grocery store, Don’t buy any chemicals, mom, don’t buy anything with chemicals in it or some such caption. Exactly. Well, it must have to do with people’s experience of chemistry and school, you know, smelly, stinky. Then there’s all the concern about pollution, that’s always labeled chemistry. What we should really do is rename the whole thing called molecular science, because people know molecules are a good thing. Even if they are not clear what molecules are exactly when they were just collections of atoms, they know because of DNA molecule, that must be a good thing. A molecule must be a good thing, even though nobody says DNA is chemical too.
You just capitulate, you just say, forget it.
Dudley Herschbach: No, it’s more accurate, I think, to speak of molecular science now because chemistry used to be all bulk, all smelly, all throw stuff together, somewhat magically, new things appear beautiful, fun, and all for those inclined to it. But now an awful lot of it is done or thought about and explained and planned and all at the molecular level. Molecular sciences is just a broader kind of field that includes material science, a good part as well. Why is it that chemistry has this bad view? We’ve mentioned connection with pollution, all that context, but I think there’s another fundamental reason why, when people encounter chemistry, as I’ve mentioned, it was my case when I first met it in high school, it seems confusing hodgepodge. You have to understand it has to do to use a fancy word, epistemology ‒ a theory or philosophy of knowledge, and chemistry is analogous to an impressionistic painting. An impressionistic painting is a marvelous thing, but if you stand too close to an impressionistic painting, it’s completely meaningless dabs of paint. You stand too far away it’s equally a meaningless blur. At the right distance it’s uncanny, it’s fabulously, you wonder how the artist created these dabs of paint, what you see in it.
Chemistry is exactly like that. If you’re the beginner, you are almost always standing too close or too far away, you don’t see what’s really there and physics you can usually reduce things as some beautiful, basic fundamentals and build from that, so the physicist tends to stand too close to chemistry once reduced it to first principle, Ah no, a terrible mess here. You can’t reduce it just to solving the basic equations because the chemist is working with a more subtle, complicated thing that you can make some connections to first principles, but you also have to feed in some empirical rationalizations and approximations and all that to construct a picture that you can talk about and think about. You can stick only to first principles nearly as much as you can in many fields of physics. The old-time biologist would stand too far away from chemistry. They didn’t want to get in all this detail. They wanted to know something, be big at something, big at the cycles and all that. Now of course the biologists or a large fraction of biology has become molecular. They want to know because they really should change a method group someplace can have a huge impact on what happens. Biologically sometimes just change one side group of amino acid and man, the consequences propagate and all.
Biology is a molecular large part of it for molecular science too. Our department here is chemistry and chemical biology now, and the same is true at many other places. That’s the nature of the beast that you’re dealing with impressionistic painting and if you don’t know how to look at it at the right distance, it’s a very confusing business, chemistry is. Chemists are used to going to a party or something and someone asks who you are. Then, “I’m a chemist”. They usually wince, and out comes a story of an unhappy experience in high school or introductory chemistry class. That has something to do with a bad connotation of the word.
Just a last quick question. How do you solve the problem at school of people not being able to get the correct distance from chemistry to really get the picture early on?
Dudley Herschbach: My short answer is you teach a liberal art. You realize it is that kind of thinking and you help them understand that our ordinary kind of conversations about many things have this character that is the level of approximation or abstraction in chemistry, that you use changes as you talk about bonding. One moment about terminal overall properties of bulk substances, another speed of reaction. They all have a different level of projection and approximation and vocabulary and all that. But the chemist in ordinary discussion goes back and forth, back and forth. fluidly. We do too in ordinary discussions of many topics. When you stop to analyze it, that’s the case. But when you are accustomed to a language, say like English, it’s a holy mess from a linguistic point of view, it’s a sloppy mixture of several other languages, and all the rest. Well, so is chemistry, and once you understand that you see, Gee.
I’ve been talking like a chemist all along, except I use different words and I don’t realize talking about people instead of molecules or institutions instead of molecular processes. But the chemist sees all these analogies and when you bring them out in teaching, I think it helps people to see. It’s so much fun to make connections. For example, one thing I love to do when I talk about the gas laws, a standard topic, you always have to discuss in the chemistry course. Suppose Hercules was confronted with a 13th labor to weigh the Earth’s atmosphere. Put it that way, because that’s a consequence, and a so-called gas law. Then I say, let’s figure out what the atmosphere weighs and it’s easy to do. Then they say, But that’s a big, big number.
How to make it meaningful? To make it meaningful, you compare it with something else. What else? Everyone knows that one atmosphere will hold up about 29 or 30 inches of mercury, that’s equivalent to 34 feet of water. It’s significant. How much pressure does that exert? It turns out that the pressure the atmosphere is exerting right now can be compared with how much you exert when you stand on the floor. We take your weight. We take the area of your feet and pressure is force pre unit area. It’s a gravitational force your weight, and it works out. You’re about 80 kilograms, more or less, your feet occupy about 400 square centimeters, and the atmosphere is one kilogram per square centimeter turns out. So if you take 80 over 400 that’s one fifth. You only exert one fifth of the pressure. When you stand up that the air does, doesn’t that make you feel lighter right away, you can dance practically. This is the way you say it to the class, it makes them see it in a different way. There are countless opportunities like this to teach chemistry as a liberal art. That’s what I mean by it.
I think on that hopeful note of the idea that we’re all chemists at heart and you can make a chemist out of everybody. I’d like to say thank you very much, indeed. Thank you.
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Nobel Prizes and laureates
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