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Autobiography of Reinhard Schinke On February 15, 1950, I was born in Hardegsen, a small town near the Iron Curtain, the border between the Federal Republic of Germany and the German Democratic Republic. My father, Bernhard Schinke, was a displaced person from the former Silesia, the part of Germany that became part of Poland after World War II. His family had had a small farm in Silesia, but they got only a tiny compensation for it from the German government. Without any other profession, the only way to support his family (his wife, Irmgard, a native-born Hardegsenian; my older brother, Herbert; and me) was to work again on a farm. Only much later did I really understand what it meant to my father to have to leave home and start a completely new life at the age of 30 or so, especially under postwar conditions. Despite financial tightness, I had a pleasant childhood, playing on the farm and in nearby forests or splashing in the public swimming pool. After 4 years of education in the elementary school in Hardegsen, the teacher suggested that I switch to the Gymnasium in the district town Northeim, about 20 km away. My parents were not enthusiastic about my spending, at the age of 10, up to 2 hours every day on the train, and they did not see higher education as a necessity for my future life. They tried to talk me out of the idea. At that time, very few working-class children went to high school, not to mention university. My brother, for example, did not get this opportunity. Nevertheless, for reasons I do not remember, I insisted and changed to the Corvinianum in Northeim, a boy’s school. The new environment definitely had a profound impact on me. For example, I became a frequent customer of the public library and took home a wide variety of books: novels, historical books, science books, etc. I did not have serious problems at school, with the exception of German. I enjoyed mathematics and sciences more than languages, and therefore, it was only logical to study physicssin Go¨ttingen, not far from home and with many friends nearby. I came to Go¨ttingen in the summer of 1969 and moved into a flat shared by several others, which was quite a new experience in Germany at that time. My parents were shocked, and in retrospect, they had very good reasons. When I visited the Mathematics and Physics Departments on Bunsenstrasse for the first time, I was not aware of the significance of these old buildings, where people like Hilbert, Heisenberg, and Born had made invaluable contributions to science in the 20th century. F. Hund was still around. Dutifully, I attended most of the necessary courses and passed the mandatory examinations. But I did not do more than what was required. In the first two years, I was mainly concerned with “saving” the world from capitalism, without notable success. In the late 1960s and early 1970s, Go¨ttingen was one of the centers of the student revolt in West Germany. Forty years later, the worldwide financial crisis was much more “successful” in illustrating the risks of capitalism. My attitude toward science changed when I started my diploma thesis after the fifth semester. The director of one of the Physic institutes whom I asked first about a thesis, tested my physics knowledge and pointed me to the re-established Max-Planck Institut fu¨r Stro¨mungsforschung (MPI-SF) across the street on Bunsenstrasse. “There they take everybody”, he said. The guard at the gate of the MPI-SF called, by chance, the secretary of Prof. Peter Toennies, and that is the reason I
studied molecular interactions for 40 years! It was not the last time that a mere chance changed my direction. While I did not spend much time on physics during the first part of my study, I was hardworking during the second part, working on my diploma thesis. It was fun to see atoms and molecules “interact” with each other, even if only by solving equations with the computer. Prof. Toennies gave me several of Bill Miller’s articles on classical S-matrix theory and wanted me to do calculations along these lines, which I did. I learned a lot about molecular dynamics during the two years at the MPI: the usefulness of classical mechanics; the beauty of semiclassical descriptions of molecular collisions; the “thrill” of comparing real experimental data (cross sections, spectra, etc.) with the results of calculations. My work was mainly numerically oriented, while my knowledge of “real” theory remained underdeveloped. Actually, this orientation did not change much during the next 35 years. Another important aspect of my time in Toennies’s department was the early contact with internationally established scientists Don Kouri, Bill Miller, Michael Baer, Alan Dickinson, Don Secrest, and others. Another visitor, who had a profound impact on the next few years of my scientific career and with whom I became friends, was Paul McGuire, a postdoc from the U.S. I completed the Diploma in Physics in the summer of 1974, and at the end of the same year, I moved to the University of Kaiserslautern and joined the group of Prof. Heinz Kru¨ger in the Physics department as a doctoral student. At exactly the same time, Paul McGuire took a position as research assistant in the same group, which gave us the opportunity to consolidate our personal and scientific relationships. The theme of my thesis was nonadiabatic transitions in atom-atom collisions, primarily the simplest one: H + H+. Coupling between electronic states is still a main topic of my research, 35 years after my first steps in this direction. While my supervisor favored a more traditional pencil and paper approach, thanks to my ignorance of sophisticated mathematical and theoretical tools, I preferred a more numerical one. Kaiserslautern was not a place that offered much entertainment to a young man in the middle of his 20s. Hiking in the Pfa¨lzer Wald became a major hobby, and the nearby Weinstrasse made me acquainted with wine. Nevertheless, I wanted to leave Kaiserslautern (at that time, the largest NATO air base outside the U.S.A.) as soon as possible, and therefore, I finished my thesis quite quickly, in the summer of 1976. Even though I did not have a clear idea of my future, it seemed natural to me to first spend a year or so abroad as a postdoc. While searching for the right placesthe location was more important than the sciencesPaul and I started to study rotational and vibrational energy transfer in atom-molecule collisions, inspired by beam experiments on H2 + H+ in the laboratory of Prof. Linder in Kaiserslautern. With Paul’s help, I got familiar with exact quantum mechanical scattering calculations as well as the infinite order sudden (IOS) approximation, which became a major tool for me for the next few years. I really enjoyed, for the first time, very close collaboration with experimentalists. We were sitting in the same building and therefore could exchange and discuss new results on a daily basis.
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The state-resolved differential cross sections that I calculated for several atom-molecule systems all exhibited a regular undulatory pattern that was distinct from the supernumerary oscillations well-known from atom-atom scattering. On the basis of what I had learned during my diploma work, I could explain them in the framework of classical S-matrix theory as “orientation-interference oscillations”, a rather cumbersome expression. Later the term “rotational rainbows”, coined by Lowell Thomas, became widely accepted. I wrote a paper about these observations and submitted it to Chemical Physics for publication. The other, much more important incident in that period was that I met Ellen Paul, later my wife. She studied mathematics in Kaiserslautern. In view of the very large disproportion between male and female students at a mostly technical university, I can consider myself very fortunate that she had picked me. At the end of 1979, I left Kaiserslautern, heading to the IBM research laboratory in San Jose to work with Bill Lester, Jr. It was my first visit to the U.S.A. California was the dream of every young German. I was more than happy to get the chance to work in that eminent research setting, and postdoctoral salaries at IBM were much higher than anywhere else. After a long transAtlantic flight, the culture shock could not have been more drastic: San Jose definitely was not Go¨ttingen or Kaiserslautern. When I arrived, Bill had just moved to Berkeley to be the director of a newly formed institute for computational chemistry. In other words, I did not see him much during the following year. He gave me a package of punch-cards with potential energies for the famous O(1D) + H2 reaction; some difficultto-read notes of the former postdoc, who had done the electronic structure calculations and who had left IBM at least 2 years before my arrival; and a classical trajectory code written by Jim Muckerman. While trying to get the calculations started, I received the referee report for the paper on rotational rainbows, which I had submitted just before I had left Germany. The report was very clear: This is nonsense; semiclassical arguments are so flexible that any oscillation in a calculated cross section, even an erroneous one, can be explained. The reviewer definitely was not fond of semiclassical theory. I was inclined to withdraw the paper and to forget this adventure, but Bill advised me to fight for it, provided that I believed in the calculations and the interpretation. Eventually, the paper got accepted and was the basis for my scientific activities for several years. I encountered heavy problems in fitting the O(1D) + H2 potential energy surface. There were two regions in coordinate space that did not want to be fitted simultaneously, until I realized that the bunch of cards Bill had given me actually contained parts of a different electronic state. After removing the misplaced cards, the fitting and the entire project proceeded very smoothly. This experience raised my awareness of the topography of potential energy surfaces. The resulting article still has the largest number of citations of all my publications. I made several friends during this year at IBM: Peter Andresen, Alan Luntz, and David Clary. With David, I played soccer on a team with members mainly from Europe and South America. We won two trophies; I had never won anything while playing soccer in my hometown. In addition to science and soccer, I very much enjoyed hiking in the mountains of California. In the summer of 1978, my girlfriend Ellen, later my wife, visited me for her entire vacation, and we made an unforgettable trip for 5 weeks through all the western states, visiting most of the national parks there. Backpacking became one of my most serious passions and remained so.
At the beginning of 1979, I moved back to Germany and was lucky to be able to go back to Kaiserslautern at first. However, at the end of my 20s, I could no longer push aside the question of my future career. I was open for both academics and industry. While exploring the job market, I resumed my work on rotational excitation in atom-molecule collisions and actually was able to interpret several new experimental studies of Dieter Beck (Bielefeld), Klaas Bergmann (Kaiserslautern), and Udo Buck (Go¨ttingen) in terms of the IOS approximation, especially its semiclassical version. In all these experimental data, which at first glance looked quite unrelated, rotational rainbows were the common theme. The differential cross sections measured by Bergmann and his group for Na2 colliding with rare gas atoms received special attention because accurate PESs were calculated by Wilfried Meyer (Kaiserslautern) and co-workers. This fascinatingsat least from my point of viewscollaboration between experiment, theoretical chemistry, and dynamical theory, all in one building, had a tremendous impact on my later research. I was particularly pleased when the Bergmann group measured the supernumerary rotational rainbows I had predicted in my first publication on rotational rainbows and which the referee had brushed off. During a visit to my parents, I also visited Peter Andresen in Go¨ttingen, who by that time had returned from IBM and held a position at the MPI-SF in the department of Prof. Hans Pauly. I mentioned that I was searching for a position. He immediately spoke to H. Pauly, and I was invited for an interview the next day. Prof. Pauly offered me a research position which I unhesitatingly accepted. At that time, it was already not easy to find a “stable” position in the German academic system. I suppose H. Pauly wanted to have a theorist collaborating with the experimentalists in his department, and my work on rotational rainbows had convinced him that I could fulfill this role. In the years to come, I had close collaborations with several experimental groups at the MPI-SF: Andresen, Buck, Du¨ren, Hack, Temps (in alphabetic order), and I enjoyed all of them. In the spring of 1980, I went back to the Bunsenstrasse in Go¨ttingen and stayed there for the next 30 years. “Periodic orbits” later would become an important topic of my research. Actually, my orbit was not exactly periodic: I had started in the department of Toennies, but returned to the department of Pauly. The conditions at the MPI-SF were excellent and remained excellent for a long time. Hans Pauly gave his research associates all the freedom necessary for scientific work; the financial support to pay students or postdocs was sufficient; the computer power, provided by the Gesellschaft fu¨r Wissenschaftliche Datenverarbeitung Go¨ttingen (GWDG), allowed me to perform calculations that many colleagues were not able to do; the institute had a highly developed structure of seminars and colloquia; and last but not least, many top-level scientists came to the institute for short or extended visits, providing ample opportunities for exchanging ideas or starting collaborations. A great asset was that students came directly from the Physics Department across the street in search of diploma theses, as I had about 10 years before. Physics students were, frankly speaking, better prepared for the kind of theoretical work performed in my research group than students from the Chemistry Department. The main benefit, however, was the very close interaction with experimentalists such as Peter Andresen and Udo Buck. I first continued with the study of energy transfer in molecular collisions, but soon was pushed into a new direction: photodissociation. Searching for a source for OH radicals, in the early
J. Phys. Chem. A, Vol. 114, No. 36, 2010 9593 1980s, Peter started a new project, the photodissociation of water in the 157 nm wavelength region, and continuously tried to convince me that this was a wonderful opportunity for a theorist. Volker Engel, my second diploma student, and I undertook first steps in this direction. However, the “beauty” of photodissociation did not immediately become apparent. The literature on photodissociation was, to say the least, unclear to us. The first so-called exact calculations had just appeared, but due to my deficits in formal theory, they were not easy to follow. The first results we obtained did not mean much to us, either; they definitely did not show the elegance of rotational rainbows. Nevertheless, after a period of agony, we experienced a breakthrough, and the photodissociation of polyatomic (mostly triatomic) molecules became the center of my scientific life. Actually, the breakthrough occurred immediately after an 8-week trip through New Zealand, with only my wife, a tent, and a backpack. The breakthrough to a large extent was based on an accurate and global PES for the first excited electronic state of H2O calculated by Volker Staemmler (Bochum). After a group seminar at Bochum, I asked him whether it was possible to calculate such a potential, and he promised to think about it. After a few weeks, he called me, saying that it was possible. Half a year or so later, I received about 200 energy points, which we fitted and then used in dynamics calculations. (Today the calculations of such a small number of points for a simple molecule like water would probably take only a day on a normal PC. I mention this in order to illustrate the enormous progress in computer power in the last 25 years.) This was, as far as I know, the first global ab initio PES of an excited electronic state and made possible the first quantum mechanical investigation of a molecular photofragmentation process including all degrees of freedom. The quantum mechanical calculations could reproduce and explain not only the more and more detailed experiments performed in Go¨ttingen, but also experiments from Fleming Crim (Madison) and Bruce Hudson (Eugene), and a consistent picture was established. As Peter Andresen always emphasized, water became a prototype for direct photodissociation. In the following years, my research group steadily grew. Despite some excursions to other fields (for example, molecules scattering from solid surfaces), photodissociation remained my main “playground”. We studied quite a number of photodissociation processes, but the collaboration with Robert Huber (Zu¨rich) on the excitation and dissociation of XNO-type molecules with X ) F, Cl, or CH3O was most notable. Robert recognized early on the need for reliable PESs to understand what’s going on in the excited state. Therefore, he always delegated one of his students to calculate, by means of one of the available electronic structure program packages, PESs for excited states, which we (mainly Agathe Untch, a diploma and doctoral student) used for dynamics calculations. The main activities of the Huber group were, of course, detailed photodissociation experiments. The close collaboration led to many visits to Zu¨rich and to a lasting friendship. Our work on XNO molecules later also involved close collaborations with Hanna Reisler (Los Angeles) and Joachim Werner (Stuttgart). After unsuccessful inquiries in Go¨ttingen, I received the Habilitation in Theoretical Chemistry from the Technical University Munich in 1988. This extra degree is not mandatory, but certainly very helpful for finding a professorship at a German university. Interestingly, the special lecture I had to present to get this degree was about the “ozone hole” which had just become well-known to the public. The ozone molecule later
became my main target for about a decade. Around the same time, I received a letter from Dick Zare in which he invited me to write or edit a book on photodissociation. After a short period of hesitation, I agreed to write a monograph, and probably the most hectic period of my life began. In 1989, I spent 6 months as visiting fellow at JILA (Boulder), and part of this period was used to organize my thoughts about the monograph, to complete my knowledge about light absorption, and to scan the literature. The pleasant atmosphere at JILA and in Boulder in general, with the beautiful mountains in the background, was certainly helpful. The actual writing started in early 1990, after the reunification of Germany. Whenever I contemplate writing another book, my wife tells me that she will leave home, or even better, I should leave home. Apparently, I was not easy to get along with during the 2 years I was working on “the book”. The number of students was at its maximum; that is, I also had to oversee several other projects. Waking up many nights and immediately thinking about equations, units, and missing p’s and π’s is not good for your health. The PC at home, on which the LATEX was done, I considered an instrument of torture. However, the most troublesome questions were: Who is going to read this? How will the community accept the book? In the summer of 1992, the main job was done, the batteries were recharged on a long holiday in Australia, and normal work could start again. In 1993, Photodissociation Dynamics was finally published, and the reviews were mostly positive. I am gratified that it appears to have had some lasting value. Having fulfilled the requirement of Habilitation and with my book published, I was ready for a professorship. My optimism was amplified by a “Dozentenstipendium” which I was awarded in 1991 from the Fonds of the German Chemical Industry. Unfortunately, only a few positions in Theoretical Chemistry were open in the early 1990s. I was on several short lists, but very good candidates were always ahead of me. To make it short, I did not receive an offer. My disappointment was not too serious, though, because I had a permanent position, and the conditions at our institute were still excellent. In 1994 I received, together with Hanna Reisler, a Max-Planck research award, which gave us the opportunity to intensify our collaboration. Most absorption spectra exhibit more or less diffuse vibrational structures. In the language of scattering theorists, they are the scattering resonances long searched for in the context of molecular collisions. In photodissociation, they are much more pronounced than in collisions, because the averaging over partial waves is very limited. Resonances in ground and excited states became my main target for the next few years. A very talented student, Hans-Martin Keller, wrote totally by himself an extensive computer program that opened up a new facet of my research: the calculation of highly excited vibrational states both below and above the dissociation threshold. It was applied by him and others to HCO, HNO, and HO2. One project that greatly benefited from the code of Hans-Martin was the investigation of the isomerization of HCP to CPH. This project began at a coffee break at an ACS conference in San Diego, when Bob Field (MIT) enthusiastically mentioned to me “drastic” changes of the rotational constant of HCP as the bending quantum number changes over a wide range, indicating isomerization. When I asked what he meant by “drastic” he answered 0.1 cm-1 or so. This, I have to admit, did not impress me at all at the time. Nevertheless, back home in Go¨ttingen, we did some preliminary calculations without really knowing what to look for. A visitor at that time, Stavros Farantos (Crete),
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got interested because of the possibility of “saddle node bifurcations” in a real molecule. To make the story short, this project quickly evolved into a worldwide activity including scientists from Japan, Greece, Poland, Germany, France, and the U.S.A. My task was essentially “managing”. Nevertheless, I learned a great deal about issues such as isomerization, periodic orbits, bifurcations, highly excited states, and effective Hamiltonians. By 1999, the main questions concerning HCP had been answered, and a review was written (with heavy e-mail and fax exchange between Cambridge, MA and Go¨ttingen). An accurate ground state PES for HCP, including very wide excursions from equilibrium, was the basis for our success. In the meantime, I had learned how to use a purchasable electronic structure program package, and HCP was one of my first attempts. (To be honest, I had figured out how to change a few lines in the input.) The construction of a global PES is dull. On the other hand, without a good potential, it is almost impossible to disentangle molecular dynamics, especially in excited electronic states, where barriers and avoided crossings are the rule. It is like climbing a mountain: Only those who have sufficient endurance, who do not question the meaning of the endeavor from the very beginning, who have learned to suffer, eventually make it to the top and enjoy the beauty of the surrounding landscape, which was hidden for most of the ascent. The most bothersome questions are: Am I on the right track? Will the PES, after several months of work, be sufficiently accurate? I calculated numerous PESs during the next 15 years for several molecules, several electronic states, and several levels of accuracy. In the beginning, I wanted to have an expert checking what I was doing. Later, I felt sufficiently confident to perform these calculations without supervision. The work on resonances in ground electronic states naturally led to the wide and, seemingly, mature field of unimolecular dissociation and reactions and, thus, to close scientific overlap with masters such as Rudy Marcus (Caltech), Ju¨rgen Troe (Go¨ttingen), and Bill Hase (Detroit). The collaboration with Bill developed into a lasting friendship with numerous visits to Go¨ttingen and Detroit (later Lubbock, Texas). The most striking result of our studies was the observation that the state-resolved dissociation rate fluctuates over several orders of magnitude, even for a classically chaotic molecule such as NO2. This, of course, raised questions about the applicability of statistical methods. In my view, it is still not finally decided whether these fluctuations have a profound impact on temperature- and pressure-dependent rate coefficients. For about 25 years, the MPI-SF had been an internationally recognized institute for physical chemistry and chemical physics (or, more precisely, atomic and molecular interactions). However, in the second half of the 1990s, all three directors, Wagner, Pauly, and Toennies, approached retirement age, and a debate about the future of the institute arose. The fluid dynamics part of the institute had been replaced a few years earlier by a department specializing in nonlinear dynamics, mainly neural networks, headed by Prof. Theo Geisel. Several plans had been proposed ranging from attracting Ahmed Zewail (before he was awarded the Nobel Prize) to closing the entire institute. The discord between different factions, including local politics, lasted for several years and lead to agony and deep resentment among both technical and scientific employees. Although chances of layoff are almost zero with the Max Planck Society, even I felt
insecure at times. After several years of indecision, two new directors were appointed in 2003: Prof. Eberhard Bodenschatz and Prof. Stefan Herminghaus. The new departments cover wide ranges of physics, chemistry, material science, and biophysics. Interestingly, a main topic of the Bodenschatz department is fluid dynamics, which had been abandoned only a few years before. The institute got a new name, MPI for Dynamics and Self-organization, and a new building ready for occupancy at the end of 2010. Most important for me, the new directors let me continue my studies of small molecules. Through all these years of finding a new direction for the Institute, I had a reasonably large research group. Financial support was provided by the Institute and by the German Science Foundation (DFG), primarily through a special research program for unimolecular reactions with Ju¨rgen Troe as the main leader. From the beginning of the new millennium, most of my work concerned ozone, an exceedingly challenging molecule. We studied both the photodissociation of O3 and its recombination. The latter part was inspired by the anomalous isotope fractionation observed in the atmosphere and studied in greatest detail by Konrad Mauersberger, director at the MPI for Nuclear Physics (Heidelberg). All my ozone activities were performed in close collaboration with Sergy Grebenshchikov, who came as a young postdoc in 1996 from Russia and stayed until 2009, after his own Habilitation in theoretical chemistry in Go¨ttingen. Without his contributions, neither project would have evolved so prosperously. Following a nomination by Pavel Rosmus, in 2002 I received the Gay-Lussac/Humboldt award of the French Ministry of Sciences, which gave me the opportunity to intensify my collaboration with French scientists. The photodissociation of ozone is a bounty, rich with dynamical niceties. Although a lot of work and patience was required, most photodissocation questions eventually could be answered. The recombination process, on the other hand, is of a different degree of difficulty. Because the stabilization of the transient O3 complexes requires multiple collisions with a buffer gas, just applying the tools known from single collisions is not sufficient. Model assumptions are unavoidable but open the door for ambiguity. Although progress has been made over the past decade by us as well as others, I see quite a number of questions still unresolved. I am aware, however, that other scientists may have a different opinion about this. During my almost 40 years in science, I had never experienced the kind of heated competition that arose in studies of the anomalous isotope effect of ozone. In view of the difficulties many scientists, especially the younger ones today, have to face before reaching a “stable” position (if they ever get one), I have to state: I was lucky. I obtained a permanent position in my early years; the working conditions were excellent, in terms of both financial support and intellectual environment; and I could choose the projects completely at my own will. The bureaucratic burden was very low. I frequently traveled, including exotic places, and visited innumerable conferences and workshops. I met plenty of interesting people from all continents, and many became good friends. All in all, I have no reason to complain.
Reinhard Schinke JP1034932
