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Biography of George W. Flynn In early 2001, the National Academy of Sciences announced that George William Flynn was one of its 72 newly elected members. Election to the academy, which recognizes distinguished and continuing achievements in original research, is one of the highest honors bestowed on a U.S. scientist or engineer and a fitting accolade for one who has made great contributions not only to research but also to the training and development of many other scientists and teachers. George William Flynn was born on July 11, 1938, in Hartford, CT, to George William Flynn, Sr. and Rose Tummillo Flynn. Though neither of his parents attended high school, they encouraged their children to do so recognizing the transforming power of education. George and his older brother Ken, who also later became a chemist, were raised in Hartford, where George attended the Saint Augustine parochial grammar school. This early education, provided by the Sisters of Saint Joseph, was legendary for its discipline and was to stand him in good stead later in life! He remembers spending many hours at the local branch of the public library near his family’s apartment, reading science fiction stories that became his earliest introduction to science and technology. In 1952 George started high school at the Morgan Gardner Bulkeley public high school, where he was elected Editor of the Classbook and managed to graduate Valedictorian of the Class of 1956. In the summer of 1955 between his junior and senior year of high school, George went to “Boy’s State” where he met another young Connecticut high school student, Nick Turro, who would become a colleague for life. George especially enjoyed high school chemistry and recalls with fondness his teacher, Harold Coburn, “[Mr. Coburn] made chemistry interesting and fun, and in his hands, at least, it seemed easy.” This positive influence was the most important factor in choosing a major when he graduated high school in 1956 and enrolled as a freshman at Yale University. His interest in Yale was kindled by another high school teacher, Lester Rappaport, who taught him German for two years. In the spring of 1956, George’s father passed away, leaving his matriculation at any college uncertain. As good fortune would have it, Yale University awarded Flynn a full tuition, room and board scholarship for four years. Yale’s generosity and the intellectual atmosphere in New Haven proved to be lifechanging events for George. At that time, scholarship students were required to work 12 h a week to contribute to their support. During his first year in college, George worked in the dining halls; however, in his remaining years at Yale, he was able to work in the chemistry department. For two years he read charts for stop/flow kinetic studies in the lab of Julian M. Sturtevant, a thermodynamicist interested in biological problems. In his senior year, George performed independent research in Sturtevant’s lab, a project actually begun during the summer of 1959 as part of one of the first NSF REU programs. His senior thesis involved isolating the acetyl esterase enzyme from orange peels and studying the kinetics of decomposition of p-nitrophenyl acetate catalyzed by this enzyme. Although this work did not lead to a publication, the experience helped solidify George’s interest in chemistry and fueled his desire to conduct independent research. When not working at his Bursary job, George spent most of his time studying, with occasional visits to Smith and Mount Holyoke as was common at that time. He was also a member
of a “below ground” senior society during his last year at Yale. George describes his college years with great fondness, noting that they were a time of great intellectual and social growth for him. Simply put, “Yale changed my life.” He graduated Yale in 1960, summa cum laude with exceptional distinction in chemistry and was accepted into the chemistry graduate programs at Harvard, MIT, Berkeley, and Cal Tech. He decided to stay in the East so that he could remain close to his mother who was now widowed and alone. So the choice came down to Harvard and MIT. He remembers a one-day car trip from Hartford to Cambridge in the summer of 1959 with his present colleague Nick Turro and a mutual friend Sal Russo (Professor of Chemistry at Western Washington University in Bellingham) to visit the chemistry departments at both schools. George admits that he did not spend too much effort comparing the faculty at Harvard and MIT, but that his decision was based primarily on the atmosphere at Harvard, not unlike Yale’s that he had enjoyed so much. In the fall of 1960, George enrolled in the Chemistry program at Harvard as an NSF pre-doctoral fellow. The first year was spent taking courses. During the summer between the first and second years of graduate school, George worked for the Connecticut State Department of Health. His job entailed measuring the fat content of milk samples, to ensure that “whole” was “whole” enough and that “skim” was “skim” enough! When the summer was ended, George returned to Harvard, and in September 1961 he joined the research group of E. Bright Wilson, Jr. Bright Wilson had a wide array of experimental research projects and began a significant foray into theory toward the end of George’s graduate career. Through course work Flynn had developed an interest in both NMR and microwave spectroscopy and asked Wilson, who had projects in both areas, if he could split his thesis between the two disciplines. Wilson agreed and George started his research trying to obtain NMR spectra of gases. Due to an accidental discovery made at the very beginning of the project, the NMR research turned out to be of more interest to another faculty member, John D. Baldeschwieler, and so Wilson agreed that George could work with Baldeschwieler on the NMR studies and would then still be able to work with him, later conducting rotational relaxation studies using microwave double resonance techniques. The research with Baldeschwieler involved obtaining NMR spectra of gases. This was problematic since such signals are typically small. Baldeschwieler suggested that George go find some gas, put it into an NMR tube and check it out. Flynn found an old tank of CH3CHF2 and set out to look at its NMR spectra thinking it would be good practice to study both hydrogen and fluorine resonances. John Baldeschwieler recalls the following about George’s initial project. “George went through all the usual trauma of a first-year student trying to set up a new experiment in the lab. For example, we needed quite high pressures to see any signals at all with our 40 MHz spectrometer, and George went about preparing the samples in 5 mm glass NMR tubes with very business-like efficiency. As I recall, however, his first sample blew up in the spectrometer, damaging our one and only probe. The subsequent samples did not explode, but I did find him one night trouble-shooting our erratic instrumentation and
10.1021/jp058069m CCC: $30.25 © 2005 American Chemical Society Published on Web 04/28/2005
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Figure 1. Methyl proton spectrum of (a) gaseous CH3CHF2 at 5.7 atm and (b) liquid CH3CHF2 collected with a 40.0 MHz NMR by G. W. Flynn at Harvard University. Flynn and Baldeschwieler had expected that the gas-phase spectrum would be similar to the condensed phase spectrum. The contrast between the two is stunning. Reprinted with permission from Flynn, G. W.; Baldeschwieler, J. D. J. Chem. Phys. 1962, 37, 2907-2918. Copyright 1962, American Institute of Physics.
exclaiming that he had found the troublesthe voltage drop across a fuse was zero!” “He brought me his first successful proton NMR spectrum of CH3CHF2 several days later, admitting that the experiment had failed, since he saw only two sharp lines. When we looked at his result more carefully, there in fact appeared to be four features in the H-spectrumsthree broad lines, with sharp features on top of the middle broad line. Furthermore, the middle feature was broader than the high and low field features.” (See Figure 1.) “It turned out that these unusual proton line widths were determined by the relaxation mechanism of the fluorine atoms. The fluorine relaxation times were determined by the coupling of the nuclear spins to molecular rotational states which were in turn relaxed by molecular collisions in the gas phase. The equivalent fluorine spins were in singlet and triplet spin states, and since singlet-triplet transitions were forbidden, protons coupled to the singlet state gave rise to the sharp feature. The unequal line widths of the broad features arising from coupling to the triplet fluorine states provided the evidence for the spin-rotation relaxation mechanism. I believe that this extraordinary first result kindled George’s career interest in relaxation processes in molecular spectroscopy.” Flynn remem-
bers the experience by saying, “I think it took John about 30 milliseconds to figure out what the spectra were telling us, but he was kind enough to let me take a year or so to understand it myself.” In addition to his research and course work, during his time at Harvard, George was also involved as a teaching assistant. One course that George TA’d was John Baldeschwieler’s firstyear quantum class, which according to several accounts was known as a “really tough class.” George sometimes substituted as a lecturer for the class when Baldeschwieler was out of town, and it was clear even as a graduate student that he was a skilled teacher who could not only present the material, but could instill enthusiasm for the subject mater. Frank Weinhold comments, “George sometimes substituted for John Baldeschwieler in the first-year quantum mechanics course, particularly (as I recall) in the presentation of Clebsch-Gordan coefficients. It was inspiring to us beginning students to see a young, bright, and likeable grad TA exhibiting such heartfelt and exuberant enthusiasm for this material. He skillfully steered us through the “copied-right” Angular Momentum Tables that J. M. Anderson had prepared a year or so before. (My only claim to his attention was finding a matrix-transposition error on page 19.)” In addition to Frank Weinhold in the 1963-64 first-year quantum class, there were several other students that became prominent theoretical chemists including Bill Miller and Karl Freed. Bill Miller says, “In later years George liked to brag in jest that all these theoretical chemists learned their quantum mechanics from him. I do not remember much about the course, but I certainly remember making friends with George!” After about a year and a half working on nuclear relaxation processes using NMR, George spent the next year and a half working in Wilson’s lab studying rotational relaxation processes using microwave double resonance techniques. A key feature of that experience was the careful, almost line by line mastery of Ali Javan’s 1957 Physical ReView paper, “Theory of a 3 Level Maser,” which taught him about the interaction of radiation and matter and was to prove invaluable when he later did a postdoctoral fellowship with Javan. While working for Wilson, George developed friendships with several other group members that have lasted a lifetime, including Bob Kuczkowski, Claude Woods, Vic Ronn, and Bill Miller, all members of Wilson’s group. George worked primarily with Peter Cox, a postdoctoral research fellow in Wilson’s lab helping to develop the microwave double resonance techniques. Bill Miller, whose office was in one corner of the microwave lab, says of that time, “I remember often hearing them curse Wilson because he was so tight with money; e.g., he made them build their oscilloscopes from Heathkits! Bright was of the old school that believed that the government’s money was his money, and he was not going to spend anything that was not absolutely necessary.” The time at Harvard made a significant impression on George. Of course Baldeschwieler and Wilson were the most significant influences, but there were others that made deep impressions. George recalls spending time discussing angular momentum with Claude Woods, saying Woods was “a genius” when it came to angular momentum. An older graduate student Bill Kirchhoff, wise beyond his years, provided much encouragement when Flynn was struggling with Wigner’s book on Group Theory. He benefited from endless discussions about experiments with both Kuczkowski and Ronn. George also made impressions on those around him. Even in the midst of a large number of bright students, George stood out. John Baldeschwieler says, “It was clear from the first time I met George at Harvard that he would
J. Phys. Chem. B, Vol. 109, No. 17, 2005 8281 become a major force in research and teaching, and that he also had great organizational and management skills. It was my very good fortune to have had a person of his qualifications as one of my first graduate students.” As graduate school came to an end, George contemplated what he would do for postdoctoral research. He decided to move away from NMR because the technique was being taken over by organic chemists and used as a diagnostic tool, and microwave spectroscopy was already a mature field. One day George mentioned to Wilson that he was interested in masers and lasers. Wilson suggested that if George was really interested in lasers he should talk to Ali Javan at MIT. Javan had been one of the pioneers in the development of lasers, having worked for Charles Townes as a student and a post-doc at Columbia, later inventing the HeNe laser as a staff member at Bell Labs. As it turned out, Javan was giving a talk that week at MIT and George went to hear him speak. Hearing Javan talk, George became even more interested in the field, so he called Javan on the phone, introduced himself, and told Javan that he was looking for a postdoctoral position. Javan invited George to MIT for the day. It turns out Javan was interested in having a chemist join the group, although, as George says, “they were probably interested in a “real” chemist not a physical chemist, but they didn’t know the difference.” George spent all day at MIT with Javan showing him around. Before leaving, George informed Javan that he was applying for an NSF postdoctoral fellowship, which if received, would provide support for his first postdoctoral year. According to the March 24, 1964, issue of “The Tech,” MIT’s newspaper, George received one of eight NSF postdoctoral fellowships for study at MIT that year, an award consisting of an “annual stipend of $5500, an allowance for dependents, and an allowance for travel to fellowship institutions.” Travel in this case consisted of a token on Boston’s famous “T” and George happily moved from one end of Massachusetts Avenue to the other, never sending NSF the bill for his journey! In 1964 when George started working at MIT, Ali Javan and Charles Townes had a joint research group. George defended his dissertation in early October on a Friday and joined the group the following Monday. Scarcely two weeks later, Townes was awarded the Nobel Prize for his work on the MASER. One can only imagine the excitement in the group. Although Townes was the MIT Provost at the time, he was very organized and came to all the group seminars. His presence was felt and he was an influence, not only on the research, but also on the students. Initially the work George was involved in at MIT centered on building HeNe lasers and tying to tune them with magnetic fields; however, soon after joining the group the direction of research changed when Patel published the first paper on the CO2 laser. Javan came into the lab one day and gave George the Physical ReView Letters article on this work. Although George did not recognize the significance initially, the development of the CO2 laser would have a profound impact on the direction of his life for many years to come. However, Javan had realized immediately that a CO2 laser could be used to study the carbon dioxide molecule. Javan further concluded that it was possible to Q-switch the CO2 laser. In the mid 1960s, everyone knew you could not Q-switch a gas laser because the gain obtained from Q-switching was based on the lifetime of the upper state. For the atomic gas lasers at the time, upper state lifetimes were controlled by the excitedstate spontaneous emission lifetimes of the atoms in the gas; these were on the order of nanoseconds. Carbon dioxide, on
the other hand has an upper state lifetime on the millisecond time scale, a million times longer than other gas lasers and comparable to that of the ruby laser, which Javan knew well. People would come into the lab and tell them, “You know you cannot Q-switch a gas laser.” However, these doubters were wrong and Javan was right, you could Q-switch a CO2 laser. George recalls that Javan had not only a great feel for the fundamentals but also a great ability to apply the fundamentals to building devices. “He not only understood the interaction of radiation and matter, kinetics, and spectroscopy, but also loved making devices and understood the basis of building devices.” George and others in the group soon got the Q-switching to work and began to use it to characterize the nature of lasing in CO2. The experiments were conducted by placing a small cell filled with CO2 inside the cavity of the laser. Electrodes on this auxiliary cell were used to strike a discharge, which populated the upper laser state, and a pulse from the Q-switched laser removed molecules to the lower laser state. Infrared fluorescence emanating only from the upper laser state was monitored to determine the range of possible excited-state lifetimes by measuring the recovery of the fluorescence signal as a function of pressure, discharge, and gas mixture parameters. One day George came into the lab and got things set up but forgot to turn on the discharge in the small auxiliary cell. In a cold (room temperature) sample of CO2, about 0.5% of the molecules are in the lower laser state. These molecules were pumped quite efficiently to the upper laser state where spontaneous emission from this level could be observed in the infrared spectral region at 4.3 µm. While George was marveling at these amazing signals coming from a cold gas, Javan walked into the lab, immediately recognizing what they were seeing. Because the emission signals for relaxation were pure exponentials, they were able to measure the decay rate as a function of pressure, which was then used to calculate the corresponding cross section for vibrational relaxation. These first studies of vibrational relaxation using lasers were published in Physical ReView Letters on August 1, 1966, almost simultaneously with vibrational relaxation and energy transfer studies in methane performed by James Yardley and Brad Moore using a 3.39 µm HeNe laser and published in the Journal of Chemical Physics. (The Physical ReView Letters paper was initially rejected by one of the reviewers, who commented that the way to study vibrational relaxation was to use the schock tube technique!) This was an exciting time to be studying the dynamics of molecules. Most spectroscopic experiments of the day were only concerned with the position of the transitions between energy states not their width (i.e., the lifetimes of the states involved). For George relaxation phenomena were much more interesting than spectroscopy, in part because they were more difficult to understand. Although he had moved from NMR to microwave to laser techniques, a constant theme had been the focus on understanding relaxation processes. This movement from one experimental technique to another helped George in another significant way. Early on he learned that one could move from one field to another without falling into a hole. As George puts it, “If you’ve seen one Hamiltonian you know how to deal with the next one when you come across it.” But understanding relaxation was even more of a challenge. How do you explain a process for which the interaction occurs on such a short scale and for which you cannot easily write down the Hamiltonian for the interaction? George recognized that relaxation studies were fairly common in NMR, but that many fewer had been conducted in the microwave region. In the infrared spectral region, corresponding to vibrational state energy differences,
8282 J. Phys. Chem. B, Vol. 109, No. 17, 2005 there had been essentially no pump-probe studies performed relating to vibrational relaxation. He decided that this was the place to make his mark by riding the new technology of intense, pulsed infrared laser sources, starting an effort that was to last more than 30 years. As his time at MIT grew to a close, George applied for faculty positions at several institutions and was made offers at Columbia, Princeton, The University of Illinois, and Yeshiva. He decided on Columbia not only because it was a top-rate institution, but also because it was in New York City, which was a key factor for a single guy. Even though Columbia was not yet co-ed (like Princeton), at least Columbia had New York with its essentially limitless social life. George wrote and submitted his first proposal to NSF before leaving MIT, spending about 10 h over a 24-h period to produce this document. The proposal entailed “the initial stages of a research project aimed at studies of relaxation phenomena in the vibrational and rotational levels of various molecular systems by the use of gas laser techniques.” George initially proposed to study the vibrational relaxation times of N2O, CO and CS2 using the corresponding Q-switch laser to pump the upper of the two laser transitions and then observe equilibration of the system by probing the fluorescence emission. He was notified by NSF before leaving MIT that his proposal would be funded. He was not exactly sure what to do (because the funding level was well below the requested amount!) so he called George Fraenkel, the Chairman of Columbia’s Chemistry Department, who told him that, of course, he should accept the award from NSF. At the time, George thought that the proposed experiments would take about 50 years to fully answer the questions he was proposing to study, and if his career lasted 30 or more years, the ideas in the proposal would keep him busy his entire career. However, the experiments were much more successful than he expected, and after 7-8 years George could no longer get funding to do these types of energy transfer studies. George moved to New York to start his appointment at Columbia in January of 1967. Operating on the assumption that a new, single faculty member only needed a place to sleep, he took a room in Columbia’s graduate dormitory where he lived for about a year and a half. He knew he would be spending most of his time in the lab or the office and did not need too much living space. According to Nick Turro, Columbia did not have any significant funding for setup in those days and the laboratories were pretty much in the condition left by the Manhattan Project in the 1940s. There was even a steam pipe in a gutter running through the floor of one of George’s labs! Despite the less than ideal conditions, George got right to work. That first year two students, Dick Bates and Steve Lundberg, joined his group and together they started to set up the lab and get the experiments working. The next year George took 5 more students and the group started to flourish. Although most of his time was spent working, George did find time for other activities. After failing to buy a single ticket to a Giant’s football game in 1967, George and Nick Turro purchased season tickets to watch the New York Jets at Shea Stadium. After a disappointing first season, George and Nick were able to watch “Broadway” Joe Namath lead his upstart Jets to the playoffs in 1968 and 1969. They even got to see some of the playoff games before the Jets won Superbowl III after the 1968 season. In March of 1969, George met a young woman named Jean Pieri on a blind date arranged by one of Gilbert Stork’s graduate students, Roy Rubin. She was an ICU nurse at St. Luke’s Hospital near the Columbia campus. On their first date, George
took Jeanie to Marchi’s, a northern Italian restaurant in the Murray Hill area of New York City. That first encounter went well, except for the drive homesGeorge got lost and ended up going through the Lincoln Tunnel, driving up the Jersey side of the Hudson and coming back into Manhattan over the George Washington Bridge, safely delivering Ms. Pieri to her apartment in Washington Heights. Fortunately for George, that faux pas did not keep Jeanie from going on a second date. After dating for just over a year, the couple decided to get married. In July 1970, George talked to Jeanie’s father and obtained his approval of the match. George William Flynn and Jean Pieri were married October 3, 1970, in St. Paul’s Chapel at Columbia University, a fitting place for their wedding considering that their present as well as their future life was tied to Columbia. Their life together has been a happy one, filled with respect, admiration, support for each other’s endeavors, and love. They have been blessed with two children, David, born in 1972 and Suzanne, born in 1976. Interestingly both children were baptized at St. Paul’s where their parents were married. Recently, George and Jeanie become proud grandparents, with the birth of two granddaughters (in 2002 and 2004) to David and his wife Debbie. It is clear that family has always been important to George. He learned early on that his children would know if his mind was on work when he was with them, and if he was not giving them his full attention. Somehow he learned to be dedicated to them when he was with them and still dedicated to his profession. During all this time, George was making a name for himself as a force in the energy transfer community. His research group began to carry out the studies suggested in George’s first proposal. At the time, George and everyone else in the energy transfer community was studying CO2 laser absorption in SF6. The system was very puzzling. SF6 absorbed a large number of photons; however, it gave off very little infrared radiation. This was a hot topic of discussion in the Flynn group at the time. George suggested that the energy was spreading all over the vibrational states via collisionssboth climbing up and down the energy ladder. Because SF6 has lots of states into which energy can be redistributed and because most of the states are infrared inactive, this would result in very small fluorescence quantum yields. George’s suggestion was received with a great deal of skepticism by his research group. According to George, this is one of the best things about American graduate students; they will not hesitate to let you know when you are making a “looney tunes” proposal. George finally prevailed on Eric Weitz to conduct some experiments to study the fluorescence emission from CH3F (MeF). One of the vibrational states of MeF overlapped with one of the CO2 laser transitions. The basic idea of the experiment was to pump a single vibrational state of MeF at 1000 cm-1 and then look for fluorescence from a vibrational state about 100 cm-1 above the pumped state. Weitz agreed to perform the experiment, but told George he would rather look instead at the CH bends of MeF, which are 500 cm-1 above the pumped state, since the fluorescence from those states is much stronger. After George and Jeanie returned from a belated honeymoon in the Caribbean in April of 1971, George expected to find the lab in disarray; instead, everyone was excited about the different results they had obtained. Perhaps the most interesting was the result of Weitz’s experiments. He had pumped MeF with 1000 cm-1 light from the CO2 laser and found emission not only at 1500 cm-1 but also at 3000 cm-1! Others in the lab were still skeptical. Insisting that MeF could not be unique, Tom Knudtson went into the lab one night,
J. Phys. Chem. B, Vol. 109, No. 17, 2005 8283 without telling anyone, and performed the same kind of experiment using whatever gases he could find in the lab. He observed the same results for three of the four gases he tried. George recalls coming home one night soon after these experiments and pacing around the apartment. Jeanie asked him what was wrong. He said nothing was wrong; rather the students had made a really great discovery. When asked if he could explain it, George put it this way. “If you want to take a trip from NY to Boston there are many different ways to go, you can start on Route 9 (Broadway) heading north, you can take a detour along the way, stop off at the beach, etc. There are 1000 different ways to get there, but there is only one Interstate 95. We have just discovered the superhighway for moving energy around inside a molecule.” After many additional studies, George was asked to write an Accounts of Chemical Research article that defined the rules that govern the “molecular vibrational energy transfer superhighways.” At the same time this work was going on at Columbia, George had started several successful collaborations, one with Vic Ronn at Brooklyn Polytechnic (later at Brooklyn College). Ronn was a friend at Harvard from Wilson’s group that George had known as a graduate student. Vic would often bring students to Columbia to conduct experiments in George’s lab, and the two friends shared resources heavily during those early years. He also started collaborating with Norman Sutin at Brookhaven National Laboratory. Together they developed the Raman Laser Temperature-Jump method with graduate student Doug Turner and Columbia undergraduate Jim Beitz. With this technique, it was possible to induce a rapid temperature rise in water using optical absorption of laser light at 1.3 µm. This T-jump method allowed reaction rates to be studied in solution that were nearly a thousand times faster than those that could be investigated by standard T-jump methods. Flynn and Sutin were 30 years ahead of their time as Raman laser T-jump is now the method of choice to study protein folding. In the 1970s Sutin and Flynn had struck up a collaboration with Don Carothers at Yale to study the folding of oligonuclotides, but DOE thought the project too biological to fit their mission. As a result, Sutin used parts of the same apparatus to study solar energy conversion, work for which he is now famous. In 1974, George, Jeanie, and David went to Paris for a threemonth sabbatical. Upon their return, Dick Zare picked them up at the airport and informed George that Sven Hartman and Will Happer, the co-directors of the Columbia Radiation Laboratory (CRL), wanted George to become a member of the CRL team. At the time, Hartman and Happer had decided to expand the research efforts of the CRL to include the departments of Chemistry and Electrical Engineering. After only a few years as a research member of the “Rad Lab,” George was asked to take over its leadership. From 1979 to 1985 he served as the Director of the Columbia Radiation Laboratory; from 1985 to 1990 he served as Co-director of the lab with Richard Osgood, and again as Director of the combined Microelectronic Sciences and Columbia Radiation Laboratories from 1990 to 2000. George had initially planed to step down as director after only a few years as co-director with Osgood; however, the two worked so well together that they decided to remain a team. George was more familiar with the workings of Columbia and Osgood more familiar with the Washington funding scene. Together they were able to play “Mr. Inside” and “Mr. Outside” to the satisfaction of all the CRL participants. During his last 10 years as Director, George made an effort to focus the research programs of the Rad Lab into a concerted effort in the fields of materials science and environmental science. After 25 years of
managing interdepartmental/interdisciplinary science projects, he finally stepped down from the last of these (managing the Environmental Molecular Sciences Institute) in 2004. While working at Brookhaven National Laboratory with Norm Sutin, George interacted with other researchers in the Brookhaven Chemistry Department. Following the work with Sutin, George began collaborating with Ralph Weston and coworkers in the application of various types of lasers to problems in photochemistry, molecular energy transfer, hot atom reactions, and the dynamics of chemical reactions. With the invention of the excimer laser, it was possible to obtain a lot of UV power relatively cheaply. Bob Quick, a postdoctoral fellow in Ralph’s group, came up with a key discovery that allowed the study of energy transfer from the translational motion of hot H atoms to the vibrations of CO2. George and Ralph published back-toback papers in Chemical Physics Letters with Steve Leone who was simultaneously investigating the same problems. Hot atoms quickly became a hot topic in the chemical dynamics community, as Jim Valentini, Dick Zare, and others used these same techniques to study chemical reactions between hot H atoms and D2 to form HD. Throughout the vibrational relaxation studies and the studies of energy transfer from hot atoms to the vibrational motions of molecules, George and the groups at Columbia and Brookhaven had been using IR emission as the detection method to study the energy transfer processes; however, in the early 80’s the detection method changed. George became aware of a new technology, infrared, lead salt diode lasers. Although there were no definite plans to use this new device in an experiment, George decided that anything with this much resolution in the IR must be useful for something. The group purchased one of these laser systems; however, it sat on the shelf for several years before any work was done with it. Jack Chu and Jim O’Neill were the first to study the collisional energy transfer from H* to CO2 with a lead salt diode laser. Together with Ralph Weston’s research group, George and his group pioneered the time-resolved diode laser probe technique, which made it possible to investigate the energy distribution in reaction and collision products on a microsecond time scale with vibrational and rotational state resolution. The sub-Doppler resolution of these instruments even made it possible to follow the translational recoil of the products of single collision events. The excimer laser made it is possible not only to create hot atoms but also to excite molecules to electronically excited states. In the late 1980s and early 1990s the group began to study energy transfer from electronically excited NO2 molecules to the vibrational states of CO2 induced by collisions. Expecting to observe a rotationally excited distribution in the vibrationally excited state of CO2, the first experiments performed by graduate student James Chou showed surprisingly that these molecules were rotationally cold. Thanks to a program written by John Hershberger, a postdoctoral fellow in the group, the diode laser frequency could be locked to the fringe of an Etalon and dragged across a spectral probe transition, providing a measurement of the Doppler line width of the various ro-vibrational transitions. It turned out that collisions that excited CO2 vibrationally left the bath translationally cold as well as rotationally cold. Once this was observed, it was clear that NO2 was internally converting back to the ground electronic state on a time scale faster than the collisions with CO2 and that the energy transferred in the collisions was not electronic, but rather vibrational. Long-range V-V energy transfer due to interaction with the attractive part of the intermolecular potential resulted in “soft” collisions that excited CO2 vibrationally but left the
8284 J. Phys. Chem. B, Vol. 109, No. 17, 2005 molecules rotationally and translationally cold. This led to the question of whether it was possible to observe collision events that left CO2 vibrationally cold but rotationally/translationally hot. When the diode laser was tuned to the high J tail of the ground-state distribution of CO2, molecules that were vibrationally cold were observed, but this time they were rotationally and translationally hot. These hot molecules were created by impulsive, “hard” interactions with the repulsive wall of the CO2/NO2 intermolecular potential. The NO2 to CO2 energy transfer work led to studies of relaxation of highly vibrationally excited molecules, such as pyrazine, with a chemically significant amount of energy. The study of collisions between these molecules, poised on the verge of dissociation, and CO2 provided a great deal of insight into the quenching of unimolecular decomposition reactions. Probably the most important break through in the study of relaxation of vibrationally excited molecules through collisions came when Chris Michaels, working in the Flynn group, determined that the state resolved energy transfer data obtain in the time-resolved diode laser probe studies could be re-sorted as a function of energy (rather than state) to obtain a partial energy transfer probability distribution function. One researcher in the field, seeing the results of this work for the first time, tried to emphasize the significance of this first P(E,E′) distribution obtained from an inversion of experimental data by describing it as the “holy grail” of energy transfer. By the early 1990s, energy transfer had become a mature field, and George thought it an ideal time to make a change in research direction. He decided to purchase a femtosecond laser system and use it to study vibrational relaxation in liquids. At about this time, John Baldeschwieler, one of George’s graduate advisors, won the Nichols medal, and George gave the after dinner toast/roast speech at the banquet in Baldeschwieler’s honor. Spending the day at the Nichols symposium listening to the talks, George reflected on the various research endeavors John had undertaken, starting with NMR, inventing ion cyclotron double resonance with Jack Beauchamp, and then moving on to gamma ray spectroscopy. By the end of the day, he had decided that femtosecond laser spectroscopy and energy transfer in liquids was too close to what he had been doing during his time at Columbia and decided to make a bigger change in research direction. He felt it was important to pick a very different area where equipment was readily available off the shelf (allowing a fast ramp up in the new area) but something with significant potential for a lasting, long range impact. George had seen how the NMR technique had changed, reinventing itself several times since he had worked in the field in the early 1960s, and he recognized the tremendous impact of NMR methods on chemistry. He decided that Scanning Tunneling Microscopy might, in the early 90’s, be developmentally where NMR had been in the early 60’s. The visualization power of STM had tremendous appeal and the potential to significantly impact chemistry in the future. Although much work had been done with STM at the time, most of it had been research in UHV surface physics and applications of STM to chemistry were only just beginning to be seen. Soon after returning from the conference to honor Baldeschwieler, George received a phone call from Jack Breen a former student of Will Castleman’s who was interested in a postdoctoral position. George told Jack that he was “looking to take a flyer” that would move the group’s research in a completely new direction in the condensed phase. When he heard the words “condensed phase”, Jack said, “I’ll take it.” Breen’s willingness and courage to move into such a dramati-
cally different research area sealed the decision for George! Right from the start, the STM was exactly what he had been looking for. In the hands of a skilled experimentalist, like Breen, the equipment was easy to set up, proved to be extraordinarily reliable, and produced interesting results almost immediately. Initial STM work involved measuring how molecules with different functional groups self-assemble on surfaces, using the STM as a means of identifying specific functional groups (dubbed STM marker groups), gaining a greater understanding of the tunneling mechanism for molecular adsorbates on surfaces, and using the STM to determine the chirality of organic molecules physisorbed at the liquid-solid interface. In 1997 George expanded the ambient STM work to include variable temperature UHV STM. Within 10 years, George’s research was entirely transformed from gas-phase energy transfer to STM studies of chemical properties at the liquid-surface and gassurface interface. The entire effort in his laboratory is now focused on self-assembly, models of soot forming chemistry, chemical reactions on oxide surfaces of environmental interest, molecular electronic properties of molecules on surfaces, and guest-host systems for nanocrystal assembly. During this same period George managed, with Rick Osgood, to put together a team of investigators that was successful in establishing an NSF Environmental Molecular Sciences Institute at Columbia. He directed that Institute for 6 years and presently serves on the executive committees of both the Columbia Nanocenter and Materials Research Center. Over the course of his scientific career, George has authored or coauthored a total of 235 publications, to date. Additionally, George is a popular speaker, having given nearly 300 invited presentations relating to his research. He has received a number of honors that reflect the quality of the science he has performed. These honors include an Alfred P. Sloan Research Fellowship from 1968 to 1970, a John Simon Guggenheim Memorial Fellowship from 1974 to 1975, the Harold C. Urey Award in 1982 from Columbia, and the A. Cresssy Morrison Award from the NY Academy of Sciences in 1983. The next year, in 1984, George became a fellow of the American Physical Society. In 1994, George received the Award for the Advancement of Basic and Applied Science from the Yale Science and Engineering Association. George is a member of the American Academy of Arts and Sciences (elected in 1997) and a member of the National Academy of Sciences (elected in 2001). Most recently in 2003, the American Physical Society honored George by giving him the Herbert P. Broida prize. George has been an active and effective citizen both at Columbia and in the science community. He has served on a large number of university and department committees. From 1988 to 1989, George chaired an ad hoc committee on science instruction. The recommendations of the first “Flynn Report” from this group created the Committee on Science Instruction (COSI), increased the core science requirement from 2 terms to 3 terms, and created the Rabi scholars program, an undergraduate enrichment program for exceptionally talented entering first year students interested in studying science at Columbia. Two of those Rabi Scholars (Seth Rubin and David Knapp) have worked in George’s lab. Almost 10 years later, a committee George chaired produced the second “Flynn Report.” The Committee on Student Service dramatically changed the way undergraduate students are treated at Columbia. In addition to leading or co-leading the Columbia Radiation Laboratory (for 21 years) and Columbia’s Environmental Molecular Sciences Institute, George has served as Chair of the Department of
J. Phys. Chem. B, Vol. 109, No. 17, 2005 8285 Chemistry and Co-Chair of the Department of Chemical Engineering and Applied Chemistry with Nick Turro. He has been a member of the editorial boards of Chemical Physics, Chemical Physics Letters, Annual ReView of Physical Chemistry, The Journal of Chemical Physics, and Laser Chemistry an International Journal and twice for The Journal of Physical Chemistry. George served as the Chairman of the American Chemical Society Division of Physical Chemistry and on the Executive Committee of the Division of Chemical Physics for the American Physical Society. Currently he is a member of the Board on Chemical Sciences and Technology (BCST) for the National Research Council, the Science Advisory Committee at Pacific Northwest National Laboratory, the Environmental Postdoctoral Fellowship Review Panel for the Camille and Henry Dreyfus Foundation, and the Basic Energy Sciences Advisory Committee (BESAC) at the Department of Energy. One of George’s greatest accomplishments has been as a teacher. Through the years, he has been as committed to his teaching as he has to all of his other endeavors. Over the last 38 years, George has helped 41 graduate students navigate their way to successful Ph.D. dissertations. He has also mentored over 30 postdoctoral researchers and a number of undergraduate students, and he continues to mentor and guide those whom he
has trained. Over the years, he has taught 9 different courses and been recognized for his excellence in the classroom. In 1973 George was honored with the 12th Mark Van Doren Award, being selected by the undergraduate students at Columbia College as an excellent teacher. George was the first and one of only two nontenured faculty members to win this teaching award from the students of Columbia College. In May 2000, he was further honored for his teaching with a Presidential Teaching Award, Columbia’s highest award for teaching. Again George is one of only a few research faculty members in the natural sciences to have received this award. Beyond the excellent teacher, beyond the academic and scientific citizen, beyond the brilliant researcher, George is an excellent person. He is dedicated to the success of those he interacts with, especially his students and colleagues. He is a devoted husband, father, and grandfather. He has inspired and continues to inspire all who know him to be better than they are as teachers, researchers, and most importantly as people. Frank Weinhold expressed the sentiments of many when he said, “Through the years, I have continued to appreciate George’s rare combination of youthful enthusiasm, deep sense of rigor, and true love of science that inspired me and other beginning students at Harvard in those early days.”
Eric T. Sevy Guest Editor
