Awards > Awardee Interviews > Interview

Interview: Hans-Joachim Freund

2014 Gaede-Langmuir Award Recipient
Interviewed by Dick Brundle & Dr. Paul Bagus, October 21, 2015

BRUNDLE:  It’s the 21st of October 2015.  We’re in San Jose, California. I’m Dick Brundle.  representing the AVS, and I have Dr. Paul Bagus with me assisting.  We are here to interview Professor Hans-Joachim Freund, in respect to his award for last year (2014) of the Gaede-Langmuir Award of the AVS.  Professor Freund was not able to attend last year’s meeting.  I think he was in Japan or somewhere and we were in Baltimore.
BRUNDLE:  So the award is being made this year, today (on Wednesday) instead.  So welcome, Professor Freund.  Now I’ve always known you as Hajo.
FREUND:  Yeah, that’s right.
BRUNDLE:  I think most of your colleagues and friends do the same.
FREUND:  My friends call me by that name.  My mother claims that this was the first word I could ever speak, I could say.
BRUNDLE:  Oh, okay.  I see.
FREUND:  So that’s how that came about.
BRUNDLE:  Okay.  So I’m going to first of all read the citation for the award.  “For seminal contributions to the understanding and development of novel physical and chemical concepts about the behavior of atoms, molecules, and electrons at catalytically active surfaces,” which covers a really broad range.
FREUND:  Indeed.
BRUNDLE:  But I’d like to start from the beginning if you’ll tell us when and where you were born, and maybe a little about the background of your family and up through secondary education to the point where you decided you were going to go into chemistry or physics or what university career you were going to take.  So please tell us.
FREUND:  All right.  First of all, I apologize that I couldn’t be here last year.  I had a RIKEN Advisory Council meeting which only happens every five years, and there was a particular need for everybody to attend.  That’s why I couldn’t come, and I was very grateful to John Hemminger to actually receive the award on stage on my behalf.
BRUNDLE:  Oh, okay. 
FREUND:  So I already placed the plaque in what my wife calls the museum.  [Laughs]
BRUNDLE:  Okay.  So you’re giving the lecture here. 
FREUND:  I am giving this year the award lecture, and I’ve done so yesterday.  Okay.  Now I was born in 1951, two years after my father returned from a five-year term as prisoner of war in the former Soviet Union.  He came back Christmas ‘49, my parents married in April ‘50, and I was born in March ‘51.  My father had to break up his career to join the army, which was particularly difficult for him because of the family Jewish background.  My mother waited for him for 13 years basically.  So I grew up in a family typical for Solingen.  It’s the knife town, right, the steel town where people make cutlery, and my parents had a small business inherited from my grandfather on the mother’s side, and that’s what they did.  I grew up in this environment, and my parents always said, “Make sure that you get a good education.”  Now education was free, and still is free in Germany, so I could choose whatever I wanted if I could do what I was requested to do.  I went to elementary school, then I had to take an entrance exam for Gymnasium, which I, to the surprise of my parents, did pass.  Then I went to Gymnasium— 
BRUNDLE:  Really they were surprised?  Were you a bit of a difficult child?

FREUND:  Well, I don’t remember, really.  I don’t think I was a particularly difficult child; I was the only child because my parents were already past 40.  So I went to gymnasium, and early on I developed an interest actually in biology and chemistry.  In the later part of the gymnasium, I had to decide on whether to go more into a language or more to the science direction. I had a fantastic biology teacher, and that was of course in the very early ‘60s.  So at that time, the most exciting thing in biology was the structure of DNA, and I was 14 or 13.  He caught my interest in this because he was talking about atoms, molecules and how the molecule is set up with the five base pairs and all of that, and that caught my attention.  I started to set up a chemistry lab at home to the dismay of my parents because I had all kinds of things there.  When I went to university—this is a little bit going ahead—I still had 1kg of potassium cyanide.  [Laughs]  I’m not sure I should talk about this, but anyway, I actually got rid of it only when I gave it to the people in the chemistry department at the university.
BRUNDLE:  I did the same thing.  I had a chemistry set, and I don’t think I had anything as bad as that, but I had things.  My parents kept that at home for about 20 years because they didn’t know what to do with it.
They put it up in the attic, and then finally I had to dispose of it.
FREUND:  In the summer breaks, I went to work to get some money.  My parents were not very wealthy.  We did have a house because that was inherited from my grandfather, and the family, the little workshop or company was close to the house, so we had some space where I could actually do this.  So I went and worked during the summer breaks, and from that I bought glassware.  So my most expensive purchase was a Kipps apparatus.  You know what a Kipps apparatus is?
FREUND:  It’s a device to make gases from.  So I still have that in my study at home.  I spent all my money on this stuff, and then I had not a very good physics teacher, I have to say.  He was a person from industry who, after the wartime, decided to become a teacher because there was a big demand for teachers in natural sciences.  But he did catch my interest for the field, so I’ve always been between chemistry and physics, even in the early days.  But it was very clear for me from the age of 15 to 16 on that I would do natural sciences.  After my Abitur in 1969, when I had just turned 18 (in Germany at that time, the start of the school year was changed from Easter to mid-year), I profited from one of my school years being only half the length of a regular school year, and so I was actually rather young finishing Gymnasium.  So I started physics and chemistry in parallel.  I studied both subjects full level, so to speak, and then I got my, what you today would call a bachelor’s degree, and then I dropped chemistry.
BRUNDLE:  Where were you for that?
FREUND:  Solingen is close to both Düsseldorf and Cologne, and I ended up studying in Cologne, that was when the student protests were had just started a year before.  I was not very political, I have to say, although all of my colleagues were very much into politics.  I just wanted to do my thing. 

So I started to study both fields, and since I had this chemistry lab at home, I had done what in the German chemical curriculum called the Biltz-Klemm-Fischer introductory lab course in  organic chemistry.  You do all the experiments with test tubes and so forth which usually takes a semester.  I did this in two weeks.  I think this that was the first time I had ever impressed somebody. I went on and I got my bachelor’s and then I dropped chemistry, as I said, simply because the people in Cologne were good on the synthetic side, but when it came to getting the background, the quantum mechanics and things like that, it was not convincing to me.  So I dropped chemistry. 

Did physics all the way through until I got ready to become a Diplom-Physiker, and then I wanted to do my diploma work—I mean the experimental work—for Herbert Walther.  He was in Cologne, a professor of physics, and at that time he left for Munich to set up the now-known Max Planck Institute for Quantum Optics.  In addition, I had just met my later wife, Susanne, and so I didn’t want to leave Cologne.  I decided to look for another advisor. The other people in the Physics Department offered not exactly what I wanted to do.  There was Dieter Wohlleben.  He and Frank Steglich were the guys with the heavy fermions. Low temperature physics was not exactly what I wanted to do.  I found someone in the chemistry department, who just came to Cologne.  He was a physicist but working in chemistry—believe it or not, in organic chemistry.  That happened to be the open chair, and they hired him for that chair.  Georg Hohlneicher came from Munich.  He was from the Günther Scheibe School in physical chemistry.  So I went to work for him and I set up a photoelectron spectrometer.  That was 1973! 
BRUNDLE:  A gas phase spectrometer?
FREUND:  No, no, no.  The Leybold LHS10.
BRUNDLE:  Ah, okay.  Yes.
FREUND:  I think we had the very first version of it.  So I worked with Polaschek.  He was the chief engineer at Leybold at the time.  Leybold’s incentive to sell these things was to also sell it of course worldwide, and they had an order from Russia, I believe.  People wanted to investigate actinides when some of them undergo beta decay, so electrons are emitted all the time from the sample.  So you had to make sure that the electrons that came from the beta decay don’t make it into analyzer if you want to do photoemission, right?
BRUNDLE:  Yes.  [Chuckles]
FREUND:  So they modified the electron optics that was detrimental for angle-resolved photoemission. I decided to look into electron optics and modify the LHS10 optics, knowledge that became useful later on when I worked for Ward Plummer as a postdoc.  So we fixed that.  It took a long time, and I did my diploma thesis on electrostatic charging of insulators in photoelectron spectroscopy.
BRUNDLE:  So you got into photoelectron spectroscopy more or less by accident?
FREUND:  By accident, yes.  Georg Hohlneicher was talking about photoelectron spectroscopy in his lectures, and so that’s how I got into it and I got interested in it and I did my diploma work.  And of course, when I finished, I sent it to the Chemistry Department and the Chemistry Department said, “No, you can’t get a diploma in chemistry because you haven’t done the graduate studies,” right, I mean the part after the bachelor’s.  So I went to physics and they said, “Well, you did your diploma work in chemistry [???].”  So I got stuck.  And then the organic chemist, Emanuel Vogel—he’s that rather well-known organic chemist—helped me.  He said, “You know what we do?  If you really work hard, we set up…” They set up a program for me that I could do within ten months, the entire graduate studies.  I didn’t do anything but working, and somehow I made it.
BRUNDLE:  And that would normally take how long?
FREUND:  It would normally take two years. So I finally went through the exam, got good grades, got a Diplom-Chemiker, and then after about a year, the rules changed in physics and they said, “Come on.  We’ll get you…”
BAGUS:  So you have both degrees.
FREUND:  So I have both degrees, and so that’s how it all came about.  Then I started to work in photoelectron spectroscopy.  That must have been the time when we met first, or a little later on.  At least one? paper I knew your name from…
BRUNDLE:  Yeah.  I don’t think I’d met you at that point.
FREUND:  No, not at that point, but not long after that, I think.  My diploma was in ‘74, and then I started to work on photoelectron spectroscopy of adsorbates in Hohlneicher’s group. He has this physical chemistry background and he was also doing calculations.
BAGUS:  Yes, I was going to mention that.
FREUND:  He was doing ab initio calculations on organic molecules, and of course since I got interested in adsorbates—I mean, CO on anything was interesting at the time, right?
BRUNDLE:  We wonder why now, but…  [Laughs]
FREUND:  Right!
BAGUS:  We were all working on it!
BRUNDLE:  Yeah.  Therefore it was interesting. 
FREUND:  Yeah.  So I learned about the work that Gerhard Ertl did in Munich and so forth, and so since everybody had worked on nickel, mainly, I was thinking of a different substrate, and of course I choose the wrong one, cobalt.  Anyone knows cobalt, if you try to clean a cobalt single crystal, you never heat it above 400°C because it undergoes a phase transition, and that of course destroys the single crystal. I had been financed during my studies by what the Germans call Studienstiftung des Deutschen Volkes. It’s a rather prestigious fellowship, which only about a percent of the student population receives. I had some money from that fellowship, in fact, more money than I ever had before, and so I bought the crystal by myself, and of course then I heated it up to 400 degrees; it was gone. Then Georg Hohlneicher bought me the second one.
BRUNDLE:  You know, I was going to ask at some point…There were many, many successes in your career.  I was going to ask whether there were any disappointments.  This must have been one!  [Laughs]
FREUND:  I will tell you a very strong disappointment.  It comes a little bit later in my time.  So just to finish that thesis project, I did cobalt.  You know Maurice Campagna in Jülich was interested in spins, and also in Cobalt.
BAGUS:  Which is not Ibach.
FREUND:  No, no.  Not Harald Ibach. Maurice Campagna later left science and worked for ABB in Switzerland.  He was the co-advisor of my thesis. I did CO on cobalt, and we started to get interested in these funny line shapes.  You know, in photoemission of carbon monoxide, you have this little extra line of 5 eV up the energy scale, and I got interested in this.  Since I had been trying to get theory going to understand photoelectron spectroscopy, I wrote a CNDO code to study photoelectron spectroscopy and calculate core hole states.  That’s when I learned about Paul— 
BRUNDLE:  Yes, and I think that’s about the time when I first met you and you were giving papers at meetings.
FREUND:  That’s right.
BRUNDLE:  So when I first met you, I thought you were a theorist.
FREUND:  That’s right, many people thought I was.
BRUNDLE:  I had no idea at that point that you were an experimentalist.
FREUND:  Exactly.  I mean, the reason was the following.  When we were looking into these shakeups, of course we had no ab-initio code as Paul had it.  We calculated these intensities and these profiles on the basis of semi-empirical calculations, but what we could do that not many other people could do, we were able to calculated inner valence spectra based on the Tamm-Dankoff technique, that Lenz Cederbaum, a very well-known theorist, now in Heidelberg, who, did his Ph.D. with the same advisor as I did, developed. This technique applied to calculate inner valence photoelectron spectra came originally from nuclear physics. It’s a CI-based (configuration-interaction-based) technique, and was attached to my CNDO code.  So we could do inner valence photoelectron spectra of molecules in the gas phase and also on surfaces.  The energies didn’t come out very well, but anyway we could see the phenomena. 

So I looked into that from a theoretical point of view and I had looked into it experimentally. Earl Muetterties in Berkeley had developed the concept of organometallic compounds, comparing them with surfaces.  I thought that was exciting because it combined physics and chemistry, and we compared our CO/Cobalt photoelectron spectra with those of mono-, di- and tetra-cobalt carbonyls. Only at the end of my thesis I realized that there was a group in the United States doing that, exactly that, and we saw that indeed, the photoelectron spectra are pretty similar for the core holes. Of course, in the valence it was different because of the differences in electronic structure. 

I did the calculations for those compounds and the adsorbate system, and on the basis of this, I sent my thesis in.  By the time I sent my thesis in, Hohlneicher had put a paper on my desk by Ward Plummer and Bill Salaneck, and it was exactly the same stuff that I had done.  So I thought, “Gee, what do I do?”  That’s when my thesis advisor helped me.  He said, “Well, you know, you can prove when you did what.  You have a lab book.  So if worse comes to worse, when you defend your thesis, we will have that available.”  Anyway, I defended my thesis in 1978, and I decided to go to work for that guy who did the same stuff that I did.
BRUNDLE:  That’s Ward Plummer.
FREUND:  Ward Plummer at Penn.  So I got a fellowship from the German Science Foundation.  I come to the bad part of the story, i.e. the question you asked initially, in a minute.  So I got a fellowship from the German Science Foundation and I went to work for Ward.  I spent some time in Philadelphia, but most of the time in Webster, New York with Bill Salaneck.  That’s when I met Charlie Duke and all these people up there.
BAGUS:  All those famous or infamous people.
FREUND:  That’s right.  And we worked on these satellites and we did sun rules.  That’s when I started to…We had a PRL and we had a Journal of Chemical Physics publication on it.  We did pressure-dependent carbonyl spectra in the gas phase and compared it with a solid, and it all worked out very well. This was between 1979 and 1981.

Before I had gone to my post-doc to Penn, I had of course talked to the people in chemistry in Cologne, and made sure I could defend a habilitation in Physical Chemistry (Remember my advisor held a chair formally in the Organic Chemistry Institute.)  At that time, there was no other way than to go through habilitation if you wanted to have an academic career. So when I came back—took another year and a half—I worked on the machine that I set up in the beginning.  Did some more experiments and so forth.  I wrote my habilitation thesis in 1982, and it was about multi-electron excitations in surface systems in comparison to molecular adsorbates.  So it was a continuation, more or less, of the work that I did as my thesis because no one else in the group of Georg Hohlneicher had continued the work.

So when I sent in my thesis, I went to the guy who told me, “Of course you can do this in physical chemistry.”  He just showed me the door and said, “No way,” and I said, “Why is that?”  I thought there was a scientific argument coming, and he said, “No.  You know, I got into a fight with your mentor, and sometimes…”  We have a saying in German:  Den Sack schlägt man, und den Esel meint man. That is, there is a donkey carrying something and you want to hit the donkey, but you hit the something on the back of the donkey, and I was the back of the donkey.  So I had already sent in my thesis, and you have to understand.  At the time you were only allowed one attempt for habilitation.  If the thesis was turned down, you have no second chance.
BRUNDLE:  That’s it.  Yes.
FREUND:  So the way it was handled was you send it to the secretariat, and if there were problems, they would give you a call, saying, “You left something in the secretariat.”  You could go pick it up as if the process had not formally started.
BRUNDLE:  I see.
FREUND:  And that was exactly what I was expecting.  By that time, I had married my wife Susanna.  We had Julia.  We basically brought her back from the United States.  She wasn’t born then, but she was in preparation, so to speak, and I was desperately looking for a job, right?  I mean, what do you do if you have a family and kid and so forth?  So I was in  turmoil.  I thought, “Geez.  What’s going to happen?”  I looked around for jobs.  I had an offer for two things.  One was in Karlsruhe to be a technician at the now KIT, and the second one was in an institute for environment control in Essen as an officer.  So I didn’t get that call from the secretariat, so obviously they did submit the thesis.  But of course I thought, “Gee.  I have all this opposition and how am I going to make it?”
BRUNDLE:  How is this going to work?  Yes.
FREUND:  At that time I had applied for a tenured Associate Professorship in Erlangen. This was the only announcement of an open position I could find in Germany. They invited me to give a talk and that went well. My Habilitation was still pending, but then on a Friday afternoon, a person called me up that I had met only briefly, Gerd Wedler.  He was a very well-known physical chemist in Germany.  He wrote a textbook in German; I’ll come back to that later. Gerd Wedler called me up on that Friday afternoon—I’ll never forget that—and said, “I talked to my colleagues.  We put you on place one on the list, and they will give you the job even if you don’t get the habilitation.”  So I don’t remember that evening.  I think I got— 
BRUNDLE:  I think you were celebrating very strongly.  Yes.  [Laughs]
FREUND:  That’s right.  So I was still expecting some problems, and on Sunday, the theoretical physicist Mühlschlegel--and he’s a very well-known theoretical physicist—called me up and said, “Listen.  Do you need to do your habilitation in chemistry?”  I said, “Why do you say that?”  He said, “I talked to my colleagues.  We all know you.  We call it chemical physics and not physical chemistry, and then the chemists can’t do anything.”  On Tuesday I was done.
BAGUS:  That’s fast.
FREUND:  So that was a real…I mean I was going through a deep minimum, and I did not know that, for example, Gerhard Ertl was one of the referees of my habilitation thesis. I was told the report was very short but to the point.
BRUNDLE:  That is typical. Ertl was one of the supporters of your nomination for this award.  It was also very short, very much to the point.  Yes.  [Laughs]
FREUND:  So of course I was extremely happy, and I went to Erlangen.  That was the place, and I worked as an associate professor for four years. My twin boys, Martin and Sebastian were born in Erlangen. I got my first German Science Foundation grant, built my first machine myself. I mean I had to leave everything in Cologne, of course, and that’s how it all got started.  I’ll just briefly go through the history. I spent four years in Erlangen as an associate professor and then got an offer for a chair in Bochum. That’s Ruhr University of Bochum.
BRUNDLE:  Yes. I visited you there when you were all set up.
FREUND:  That’s right.
BRUNDLE:  And I think that was actually the first point I realized how much experimentation you actually did.  [Laughs]  Yes.
FREUND:  Yeah.  It has to do with the fact that because these other prominent experimentalists had done the same work that I did and we only added this little theory part, that…It was not valued, I think.  Anyway.  So I was in Bochum.  I was nine years in Bochum, and then I had a couple of offers to other places which I never talk about, but it’s a fact, and then I got this position in Berlin in the Max Planck Society.
BRUNDLE:  Yes, and you’ve been there ever since.
FREUND:  I’ve been there ever since.  I’m not planning to leave anymore because I have only four more years before I retire.
BRUNDLE:  I suppose it was after you moved there that you really kind of switched from working on metals to oxides.
FREUND:  To oxides.  That’s right, but we already started in Bochum.
BRUNDLE:  That’s a very difficult area to deal with.
FREUND:  Exactly.  I mean, I could name a few prominent surface scientists who told me, “You cannot be in the right frame of mind to go to these materials.”
BRUNDLE:  True, because there were people trying to work on oxides before, some quite good people, and they never seemed to go anywhere.
FREUND:  No.  That’s true.  So that’s— 
BAGUS:  Well, if you work on a single crystal oxide, it’s not very interesting.
FREUND:  Well, the problem is of course that if you are a photoelectron person and you work on this oxide, many of them are insulators and so you have this charging problem that I worked on as a diploma student very much.  So you can’t really get any decent binding energies and things like that.  So we started to think about this, and by that time, I think exactly at the same time, Wayne Goodman had started to do thin films and I did not know about it.  I was visiting Gabor Somorjai in Berkeley and Wayne was giving a seminar, and I talked to him the first time.  I said, “You don’t believe it, we do exactly the same thing.”  He was working on, what was it, titania films, and I was doing aluminum oxide and nickel oxide as thin films grown epitaxially on these films.  That has a big advantage.  You don’t have charging problems.  Then of course you have the question, does the thin film represent what you really want?
BRUNDLE:  So it was Wayne Goodman that really was the influence on you to try it.
FREUND:  Well, no, no.  No, no.  We were doing it in parallel. 
BRUNDLE:  Oh, okay.
FREUND:  I met him and I realized he does exactly what I was doing.
BRUNDLE:  I see.  But he was doing it on titania.
FREUND:  But he did not know what we were doing.
BRUNDLE:  I see.
FREUND:  And since then, we had been good friends and been exchanging ideas and so forth.  So yeah, that’s how it…
BRUNDLE:  But why did you move into the oxides in the first place?
FREUND:  Oh.  Yeah.  Well, I was clear that either you work on the fundamentals of photoemission, going to time resolution or something, or you use the technique and apply it to something interesting. In Erlangen, Wedler was a person working in catalysis.  Oh, he was also working on thin films, metal thin films, and I didn’t have that in the back of my mind at all, when we started to work on thin oxide films, because with metal films the charging doesn’t play a role there.  But maybe it’s hidden and you don’t always remember.  But Wedler was a person who was connected to catalysis, and I got interested in this. 

So in Erlangen we did the first papers on CO2 activation.  Actually, I think…I’m not absolutely certain, but I think we were not the last one who realized that you can make CO2 minus, which is an intermediate that was only recently recognized again. So I got interested in catalysis and I thought, “What can we do to develop the idea further?” Of course there was all the work on metal surfaces, and people argued, “Well, the reason why we work on metal surfaces is because catalysts often have nanoparticle structure.  They have facets and the facets are ordered, and they look like a single crystal of a metal and so we use the single crystal.”  I was not very experienced in the catalytic literature, but I did realize that catalyst people talk a lot about the influence of the support onto the particle.  So I thought, “Gee, if we want to get a step further from the metal single crystals, we have to do something that models this interaction of the support with the nanoparticles,” and that’s how this idea with the oxide, which is a typical support for a nanomaterial, came about.
BRUNDLE:  Yes, and then the nanoparticles on the surfaces.
FREUND:  On the surfaces, right, and I was— 
BRUNDLE:  Which beautifully fits in with the world’s current fascination with anything that’s nano.
FREUND:  Yeah, yeah, but at that time it was not in vogue at all. Anyway, when I went to Bochum, I had this chair which was very well funded.  I mean, I worked with six or seven technicians.
BRUNDLE:  And lots of instruments.  I saw that.
FREUND:  And lots of instruments.  I got a good startup package, and I had 30 Ph.D. students at the time—I mean not in the first year, but developed over the…So I had a very strong, very good group, and I was very, very lucky that I had a person (Dr. Heiko Hamann) who was working with me who got along with students extremely well.  I mean I do get along with students well, but he did it very, very well.  So most of the people that made it out of my group into academic positions I attracted in bulk from the local students, and I think it’s like seven or eight out of my cohort of people.  So I had very good people and we started working on it. 

So because Klaus Müller—you know, he’s an Erlangen physicist.  Those people who do LEED all know him.  He’s the inventor of the back-view LEED.  He actually applied in the German Science Foundation for the first so-called Forschergruppe.  In the Science Foundation in Germany, you either have individual grants or you have group grants, and there is are collaborative research centers for about 15 or 20 PIs.  It’s a large group of PIs working together on a broad theme.  Or you have the smaller version of that with only four or five groups, and that’s called a research group, Forschergruppe, in German.  That construction of a Forschergruppe was only used before in the medical sciences.  There was no single natural sciences Forschergruppe.  They’re always these big consortia.  Müller said, “Let’s do something in Erlangen,” so we got this first thing in Erlangen and I copied it in Bochum.  We got a grant, and then of course my colleagues started.  That was the first collaborative grant that was ever acquired in Ruhr University of Bochum chemistry, and that sort of got the ball rolling.  Then we started to do aluminum oxide with particles on it.  We had Henning Neddermeyer in Physics in Bochum on board, who is a good friend of mine—he’s now turning 80.  Manfred Baerns was also involved.  He was the technical chemist.  He had the expertise in catalysis. Together we got in going.
BRUNDLE:  Got it going.  Yeah.
FREUND:  Yeah, and then from there on basically we concentrated on oxides.
BAGUS:  Well, and also around that time you started working closely with the theorists at…
FREUND:  Yeah, with Volker Staemmler.  Of course.  I mean I realized…I forgot to say that.  As you said, Dick, you knew me as a theorist, so to speak.  I realized if you really want to do theory, you have to concentrate on it.  You cannot do this as a side if you want to do the real thing, and I’ve kept it that way until this day.  One of the first people who were also part of this consortium in Bochum was Volker Staemmler, a student of Werner Kutzelnigg who held the chair in Bochum.  That was a very, very fruitful collaboration, still active until this day, actually together with Paul also.  Since then, it has really been crucial for the efforts that my group has been involved with, to have very close collaboration with theory.  So having this close collaboration between theory and experiment I think is a great thing.
BRUNDLE:  Yes, and in my experience it’s…I wouldn’t say it’s rare, but it’s somewhat unusual to find theorists who are willing to really try and understand what experimentalists are doing.
FREUND:  Exactly.  In particular at that time.
BRUNDLE:  Paul here does.
FREUND:  At that time it was difficult to get theorists involved. Paul is an exception!  I mean, I got along personally with Werner Kutzelnigg very well, but he would never get into something because we do an experiment on it. It has to be theory sort of for theory, not for experiment.
BRUNDLE:  Whereas Paul would come into my lab at IBM and ask how things would work, and then he got dangerous at times.  He’d ask me, “What does this knob do?” and he’d start turning it.  [Laughter] 
FREUND:  Yeah, yeah.  [Laughing]  No, I can see that!  I can see that.  Yeah.  No, and so I think this is a blessing, and I think it’s only during the last few years that these collaborations have become common, right?
BRUNDLE:  Yes.  I always suppose the driving force for that was simply because it was harder and harder to get funds, and if you put more groups together, you were more likely to get something that would last long enough that you could actually achieve something.
FREUND:  That’s right.  But on the other hand, I also see a development that I feel is a little dangerous.  I mean we do experiment and our observables are connected with the material that you look at.  When I see what people do nowadays often, they do a density functional calculation for a material.  First of all, they do it for a material that they can do it for, which may not be the material that you’re really looking at, and that, they even don’t worry about how the data that you’re looking at have been observed—I mean, what the quantum mechanics of the observation process is.  Say, for example, in photoemission, if you take a ground state calculation, it may not be at all appropriate to do this, as Paul has pointed out.
BRUNDLE:  Yes, many times.  [Laughs]
FREUND:  Many times.  I’ve always said one of the landmark papers I remember was—and I didn’t know about it—on O2 molecule O1s photoemission in the gas phase, and you see the split of the O1s because it’s a triplet ground state, right?  This has to do with creating a hole, and so people don’t take that into account, often times..
BRUNDLE:  Yes.  Well, I think there’s so much pressure to publish and get known.
FREUND:  Exactly.  Yes.
BRUNDLE:  Particularly on theory, you can concentrate on the little bit that you can do and you find something that looks exciting.  But what you should do is now see where that fits with a whole bunch of other things.
FREUND:  That’s right.  That’s right.
BRUNDLE:  But there’s too much pressure to get those out.  [Laughs]
FREUND:  Yes, but I think if you want to become really a well-known and respected theorist, that’s what you have to do.
BRUNDLE:  Eventually you have to do that, yes.
FREUND:  Eventually you have to do it.
BAGUS:  Well, in the old days, theorists spent part of their time developing methods and part of their time applying the methods, and Staemmler did that extremely well.
BAGUS:  I think now we’ve gone from a point where Kutzelnigg, for example, would say, “It’s the method that’s beautiful,” to the point now where many people say, “The only thing that interests me are the applications.”
FREUND:  Exactly.
BAGUS:  And I think that both extremes are unfortunate.
FREUND:  Yes.  So in that respect, it is important to work with theorists who understand this whole connection, and I’ve been very fortunate that I have had always people to work with who really…
BRUNDLE:  And another thing, at least from my point (maybe not yours), when I work with theorists, I also have to believe that they will understand that I cannot understand everything they’re doing.
FREUND:  Oh, absolutely!  Absolutely.
BRUNDLE:  And they’re going to have a long time explaining it to me in detail until I get a grasp of what it really means, and a lot of theorists don’t want to.  It’s like, “You don’t understand this?  Well, I’ll go and talk to somebody else,” you know.  [Laughs]
FREUND:  But it is important, first of all, to be in contact to a person, a theorist that you respect.  But then of course there is another component which I think is a central component of science, and that is trust. You have to have a person where you know that if this person says, “We do the details right,” that is a correct statement because there is no way for someone from the outside to really see this.  As I said, again, and I can only repeat it over and over again, this for me has always been extremely important and I have been very fortunate.  I’m happy with the fact that I do not understand all the details of how the wave function has been created numerically, but I do understand, or I think I understand the quantum mechanics so I can sort of communicate, and that’s very important.
BRUNDLE:  Okay.  In looking through your CV, you’ve received many other awards.  Some of them I know what they are, some I don’t, and there’s one that intrigued me that you got recently was from the European Academy of Sciences.  I don’t really know what that is, and what is the award?  Can you say a little bit about that?
FREUND:  Yes.  Well, there are several…When it comes to academies, Europe is funny.  Germany is particularly funny because we only have since about ten years now a national academy.  We never had a national academy.  We have regional academies, and that was one of the reasons, I think, why in Europe people felt that we need a European academy.  So there is the Academia Europaea, which is seated in London.  That’s one, and then there is another one which is called the European Academy of Science.  These two are sort of parallel organizations.  Many members in one are also members in the other one.  I don’t know whether you referred to the Blaise Pascal Medal.
BRUNDLE:  Yes, that is the one.
FREUND:  That is that they give every year or every two years a number of awardees. Blaise Pascal…who was a mathematician, right?
BRUNDLE:  Yes.  When I read down, I saw that and it caught my eye.
FREUND:  Yeah, yeah.  they give it for physics, for chemistry, for material science, and I think I got it for material science.
BRUNDLE:  Material science, yes.
FREUND:  Basically what happens in the process is that previous awardees get together and try to identify people who would be worthy awardees, and that’s how this happens. I didn’t know anything about it.  I got a letter in the mail that said, you know, it happened.
BRUNDLE:  I see.
FREUND:  But it’s trying to identify people who could be worthy awardees, and the European Academy of Sciences has this award system.
BRUNDLE:  Well, to have anything that’s across countries like that is quite unusual.
FREUND:  Is a good thing.  England, of course, has basically a national academy in a way, the Royal Society.
BRUNDLE:  Yes.  Well, the.  You know, in England everything…like The Chemical Society because there isn’t another one in the world.  That kind of thing, yes.  [Laughing] 
FREUND:  Of course.  Of course.
BRUNDLE:  British are good at that.
FREUND:  Yeah, yeah.  But the Germans have only…  They have very old academies.  In fact, the Leopoldina is one of the oldest, if not the oldest, of the  German academies.
BRUNDLE:  I suppose that’s because Germany as a country isn’t that old.
FREUND:  That’s right.  Exactly.
BRUNDLE:  So you have all the separate states.  They all have their separate…
FREUND:  Yes, exactly.  That is exactly the reason.
BRUNDLE:  Yes, for how it came about.
FREUND:  Right.  They finally decided between the former Prussian Academy of Sciences, which is now the Berlin-Brandenburg Academy of Science, and the Leopoldina, that the Leopoldina should represent the National Academy.  I happen to be member in both of them. The issue is settled.  So there is now a national academy that represents Germany to the outside.
BRUNDLE:  Okay.  Paul, you have said very little, so do you have any specific questions?
FREUND:  Sorry.  I’ve been dominating this time.
BAGUS:  No, no.
BRUNDLE:  No, no.  But I’ve been asking the questions, and Paul…I want to give him a chance. 
BAGUS:  One of the things that you showed very nicely in your talk is how important it is to have a group of really good people focusing in on a topic, but it’s not a simple task to arrange and support such a group?.  Are there thoughts that you’d like to share on how one can do that?
FREUND:  Well, you know, I have been trying…First of all, you have to interest students.  That is the most important thing.  You have to excite them about the subject, and you have to show to them that this may be useful and that it’s interesting.  Once you have the students working for you, you have to make sure that the climate, the personal climate in the group is trustful.  That is the most important thing, that nobody has the feeling the boss is controlling everything in the sense that he sort of pulls the strings between the people and so forth, but they all work together.  I’ve always tried to do that so that people base their interaction on trust. My door is always open (if I’m there) and my secretary will not make an effort to keep people out.  I have always trusted the senior post-docs who run particular parts of the group and they trust me that I will support them.  I think that’s how it should be done. If dramatic things happen in your life this becomes particularly important. When Susanne passed away in 2004, and my children went through difficult times, trust was the most important thing. Now I am happily married again with Tatiana, who brought a fourth child, Jan into the patchwork Freund family. Trust is the most important aspect.
BRUNDLE:  That’s how Gerhard Ertl ran his group as well.
FREUND:  That’s right.  Once I had been asked by Angewandte Chemie to write a little article about—If you publish so many articles in Angewandte, they will ask you to write a little thing.  They ask good questions, and as they say, “Who are your role models?
BRUNDLE:  Your influences?
FREUND:  No.  The role models, people whom you would take as an example—And I said, “Two.  Michael Polanyi and Gerhard Ertl.”  Gerhard Ertl, because he has been always…Firstly, he was one of the first people I met who could really express complex things in very simple words, and secondly, he is not a polarizing person. In many discussions, when he realizes people made a mistake, it’s just by a simple sentence that makes people realize they made a mistake and they’d better correct it. It’s this kind of way of dealing with people I have always admired with him. Michael Polanyi, who worked in the same building that I’m working in now, must have had a similar personality. He has had very famous students like Eugene Wigner, who did his Ph.D. in Berlin. Michael Polanyi basically let people work on very diverse fields.  If you look at Polanyi’s life, John (his son) is a Nobel Laureate.  Michael Polanyi never won the Prize. John Polanyi was born in Berlin, and he told me stories of his father.  After Michael Polanyi went to Manchester, actually, when he had to leave Berlin as a Jewish Hungarian refugee, so to speak, he has been cited to have said: “Berlin was the best time in my life.”  It’s not putting Manchester down, of course. 
BRUNDLE:  I’m glad since I’m a graduate of Manchester.  [Laughs]  But yes.
FREUND:  Michael Polanyi must have run his group in the same way.  I just was in Sapporo because the Catalysis Center in Sapporo, which was founded by Horiuti, who worked with Polanyi, celebrated the reinstallation of the Catalysis Institute. There’s a famous mechanism in ethylene hydrogenation.  It’s called the Horiuti-Polanyi mechanism, and that work was done at the Fritz Haber Institute in the 1920s.  It was published only after Polanyi had left to Manchester.  One of Horiuti’s student came to me when I was in Sapporo and I mentioned this, and he said, “You know, what Professor Horiuti told us about Professor Polanyi is that he must have been an extraordinary person,” and that’s why, not knowing about this at the time when I wrote this little question and answer piece in Angewandte, I choose those two people as my role models.
BRUNDLE:  So those are your examples.  I guess we’re getting near the end here, and we have a question we always ask.  The situation today, do you have any advice to give to a young student about how or why you should go in a certain direction?
FREUND:  Right.  I mean, I am far from giving people really advice.  I have always thought that they should make the decisions themselves.  I’m not the person to give them advice.  But what I always keep saying: Do what you really burn for.  Do something that you really like to do.
BRUNDLE:  That’s really interesting because almost word for word, that was the same as Charlie Campbell’s answer to me yesterday in this room.
FREUND: The only way to really make it is to have a goal and live for it.
BRUNDLE:  Okay, Paul.  Do you have — 
BAGUS:  There is always a danger of having a goal which is too specialized.  That was what Dick mentioned, and Hajo, you said as well.  We all studied CO on metals far too long.
BAGUS:  Although it’s still possible to study it and learn new things…
FREUND:  Absolutely.
BAGUS:  …as you did for CO on gold.
BRUNDLE:  But we didn’t study it in isolation because so many people were working on it.  There are people who start on a thing and work pretty much in isolation.  They don’t interact with other people, and they may have a whole career of that.  But you can’t really go as far if you work that way.
FREUND:  Right, and perhaps there is one thing that one should mention.  There was a time when people here in the US created this phrase, “Surface science is dead”.  That was, in a very unfortunate way, transported to Europe where it, fortunately, never really found a good, fertile ground because surface science is still strong, at least in the country I live in. Surface science is far from being dead.  Surface science is very much alive.
BRUNDLE:  But it’s mature.  [Laughs]
FREUND:  It is mature because we have understood CO on nickel very well.
BRUNDLE:  Yes, and things like it.
FREUND:  But it is very useful for many, many different things.  It’s just unfortunate that you always need a different buzzword, although in principle you do the same thing.
BRUNDLE:  Yes.  Like Nano. I usually say “Well, we’ve been working sub-nano, at least in one direction, for 30 years by now!” 
FREUND:  Pico!  Pico!  Yes.  Absolutely.
BRUNDLE:  But keep quiet about the other two directions.  [Laughter]
FREUND:  That’s right.  But I mean it is, yes.  Chemistry is pico by definition. Bond lengths.
BRUNDLE:  Okay.  Is there anything further you’d like to add?
FREUND:  Not really, no.  I thank you very much for the interview.