I was born in Hamlet, North Carolina, on December 5, 1939. I was the only child of Caleb Henry and Evelyn Pelot Cooper Lineberger. My father worked for the then Seaboard Railroad (now part of CSX). My mother, after a period teaching elementary school, was a full-time mother and homemaker. My father was the ﬁrst member of his family to earn a college degree (civil engineering, Clemson University, 1929 was a bad year to look for a job). My mother was among the ﬁrst of her family to attend any college at all. While my parents were by no means academic or scholarly, education was a highly valued asset, viewed by them as the only path to a better life.
My father’s family immigrated to North Carolina in the 1850s, with part of the family going into railroading and the other part going into the textile industry. My mother’s family came from French Huguenots who had immigrated to the south sometime earlier. With the railroad tradition of frequent moves, I lived in Charleston, South Carolina, from 1941 until 1947 when my father was transferred to Tampa, Florida. I remained there until 1957 when I began college.
My parents deﬁnitely knew the value of providing stimulating items for a child to play with. At age six or seven, my father brought home a collection of electrical junk from the railroad: old hand-cranked telephone generators, wires, buzzers, bells, some light bulbs, and a few batteries. He suggested I play with these, and I discovered the fascination of seeing sparks ﬂy, lights light up, or bells ring when I turned a crank. This began a long interest in electricity. I then found the materials to build a crystal radio and was unbelievably proud to ﬁnd that I could hear radio stations on something that I had built out of junk. After moving to Tampa, my interest in radio led me to become an amateur radio operator at age ten, and I remained very active as a ham operator (W4YLL) through age 16. During this time, I learned the completely empirical art of building instruments without knowledge. I passed the electronics examination and the Morse code speed test required for my amateur radio operator’s license. The electronics examination required the use of algebra, but I passed it without any mathematics training, and with no understanding of what Ohm’s Law meant. I could solve moderately complex electrical circuit problems, but I had no idea what I was doing. In any event, the amateur radio interest led me to designing and building high power transmitters, receivers, and large directed array antenna systems so that I could communicate via Morse code with other amateur radio operators around the world. One of my proudest achievements was propagating a multibounce 14 MHz radio signal essentially around the earth. I computed the path length by the time delay of the weak echo of my transmission. It was at this point that I decided, at age 12, that a career in electrical engineering was what I wished. Based on this mature observation, I decided I would go to Georgia Tech, and major in Electrical Engineering. I even knew who my roommate would be. Amazingly, all of these things actually happened. Toward the end of the ham radio activity, I decided it was time to do more outdoor things, and I went through Cub and Boy Scouts. At around age 13, I completed the requirements for Eagle Scout Rank. Typical of too many of the things that I did at that time, upon completion of my Eagle Scout goal, I simply lost interest in the activity.
My interest in chemistry began when I was in high school. I had a terrible teacher for high school chemistry, but he really did not seem to want me in the class anyway. The result was that we both agreed that it would be much better if I simply spent class time in the chemistry laboratory by myself and attended class only to take exams. This arrangement worked out beautifully, except for a few minor explosive events. It certainly drove my interest in chemistry enormously. The culmination of my high school chemistry experience was to put on a demonstration for a major parent-teacher meeting held in the high school auditorium. The school allowed me complete freedom (unheard of today) to assemble demonstrations. Among other things, I carried out a large scale thermite reaction that left some burn marks on the very high ceiling of the auditorium. It was quite impressive. Other early chemistry experience included appropriately coating some of the hallways of my high school with nitrogen tri-iodide late at night, and then watching with great delight the explosive results as the building was occupied the next morning. I was never caught.
My last two years in high school were spent developing a science fair project. At this point, no teachers were interested in working with me, so I was totally on my own. I read a fascinating article1 by Erwin Mu¨ller in Scientiﬁc American. Using high-ﬁeld He+ ion emission from an atomically sharp tungsten tip, he obtained an emission image of the needle tip that clearly resolved individual tungsten atoms. I had never imagined that one might be able to see “directly” our atomic world. Seeing his images of individual atoms was a life-changing experience for me. I immediately set out to build a He+ ﬁeld ion emission microscope for my science fair project. The electronics, tip preparation, and phosphor screen preparation all looked straightforward to me. They could be made with the kind of junk that I kept in my bedroom. The required high-vacuum system was another matter, however. My parents decided that they had no choice but to humor me. Over the next six months, they drove me over much of the state of Florida in search of vacuum components that I could beg, borrow, or steal. About two weeks before the science fair, I had to face reality and admit that my project would not be complete in time, if ever. I quickly switched to something much simpler, albeit less interesting, less likely to be rewarded, but achievable in a short time. Falling back to my radio experience, I built a small, near-infrared transmitter/ receiver and demonstrated relatively high quality music transmission over a modest distance. I used collimated infrared radiation that could not be seen. No big prize for this project. This whole science fair process was a prime example of a circumstance in which informed mentoring would have been invaluable. There was precious little evidence that I would have accepted advice, however.
By the time I arrived at Georgia Tech, I was beginning to have serious misgivings about a career as an electrical engineer. With my usual sophistication, I had read the titles of all of the courses that were in the electrical engineering curriculum (Circuit Theory, Electricity and Magnetism, Antennas, and the like) and decided that these courses could teach me nothing, because I could already build all of these things. This great naïveté was not good, but it seems to continue. So I thought I would become either a chemistry or physics major at Georgia Tech. However, I quickly discovered that the physics and chemistry courses had essentially no mathematics for the ﬁrst two years. In contrast, electrical engineering courses required the use of calculus in the ﬁrst year and differential equations in the second year. I followed my mathematical love and became an electrical engineer.
However, the choice of an electrical engineering major led indirectly to my ﬁrst remarkable experience in chemistry, one that would shape the rest of my career. With all of the other courses I was taking, I could only enroll in the most basic general chemistry class as an entering freshman. This large class was taught by a person who turned out to be a wonderful inspiration for me, a young assistant professor named Peter Sherry. At the end of the ﬁrst examination in this rather boring class, Peter asked me to come to his ofﬁce. He told me I was wasting my time in his class. He then said that he would like me and two other students to stop attending class, and instead meet with him three evenings a week to learn physical chemistry. These meetings continued for a year, in lieu of taking general chemistry. It was an unforgettable experience, and undoubtedly launched me on my present course. Peter had a similar effect on another freshman student one year later: Bill Miller. This is of course the Bill Miller of Berkeley. A quantum chemist, Peter Sherry was never widely known or appreciated, but he truly was a remarkable, dedicated, and inspiring educator.
As I continued my undergraduate education, I tried to follow my father’s advice: get a degree in engineering, followed by a Master’s degree from a business school (Wharton was his choice), and also be very involved in extracurricular activities on campus. I did just this for my ﬁrst three years at Georgia Tech, ﬁlling every hour with activities that left no time to learn anything. I was fully on the advised track. However, in the last quarter of my junior year, I took a class called “The Physical Basis for Electrical Engineering” taught spectacularly by a new faculty member, John Hooper. This class brought back the excitement generated years earlier by the Mu¨ller paper and led me back to my true scientiﬁc love, an atomistic understanding of nature.
The ensuing change in plans resulted in my canceling all of my extracurricular activities and taking a full-time job at the Georgia Tech Engineering Experimental Station (Georgia Tech equivalent of MIT’s Lincoln Laboratories). I began independent work on a project to evaluate the electrical, thermal, cohesive, and corrosion-resistance properties of tungsten and gold thin metal ﬁlms for use in the electronics industry. This very applied project was funded by the Western Electric Company (procurement wing of the AT&T/Bell Laboratories complex). I ﬁnally got to build and use the vacuum system that I coveted for my failed high school science fair project. Several not very interesting technical reports resulted from this work. More importantly, I learned the joy of working in a laboratory environment. I also ﬁnally recognized the complete futility of my proposed science fair project. One amusing sidebar from that time is that a high pressure sputter apparatus developed in that laboratory2 was eventually modiﬁed to become our workhorse source of metal cluster and metal oxide anions.
The job at the engineering experimental station and a full course load kept me busy during my senior year. I began to think about graduate school and decided to stay at Georgia Tech to obtain a Masters Degree in Electrical Engineering, working with John Hooper and his Ph.D. Advisor, Earl McDaniel, Professor of Electrical Engineering and Physics. This decision was motivated in part because my ﬁance´, Aileen Jeffries, needed two more years to ﬁnish her B.S. in Physics at Emory University. Georgia Tech did not admit women at that time.
As it turned out, graduate study at Georgia Tech was a very good decision, and I ended up completing my Ph.D. there, jointly advised by John and Earl. I was a graduate student from 1961 through 1964, and it was a wonderful experience. I was placed in an empty laboratory in Electrical Engineering, and John and Earl set out to develop a new research program for me. They insisted upon my participation from the beginning. We collectively designed an electron-ion crossed-beam apparatus. I contributed to a proposal to Oak Ridge National Laboratory to construct this apparatus and to obtain absolute cross sections for electron impact ionization of alkali cations. This work would support fast ion diagnostics for the laboratory’s thermonuclear fusion research program. The proposal was funded, in spite of one referee who pointed out that my mass spectrometer was a pure electrostatic device and surely we knew that electrostatic ﬁelds did not separate monocharged ions by mass. In spite of undergraduate courses, I really had no clue that the proposed device could not work. In any event, a complete crossed-beam apparatus was constructed and used to measure absolute electron impact ionization cross sections for Li+,Na+, and K+ ions from threshold to 1 keV. I worked very hard to determine quantitatively the error bars on the absolute cross sections that we measured. I felt conﬁdent that all systematic and statistical effects had been properly assessed. To my dismay, reviewers stated that the experimental results were very impressive but our claimed error bars surely represented a lower bound to the actual errors in the measurement. We made no changes to the manuscript, and it turned out that our error analysis was correct and even a bit conservative. However, a sense of paranoia over errors persists even now, and everyone in my group knows my belief that a measurement without deﬁnable errors is of little value, as it tests nothing, not even the existence of the claimed products. This trait is part of why our initial measurement of the methylene singlet-triplet splitting was taken seriously, and why the fact that our result was eventually shown to be incorrect was somewhat embarrassing. However, I do take pride that our full analysis of the initial methylene Communication stated that the presence of vibrationally hot anions with a state distribution that we could not alter experimentally would invalidate our conclusion.
Returning to graduate school issues, there were many other lessons learned from Earl and John. Not the least of which was the concept that scientists should cooperate in their quest for new knowledge. The following story shows one way Earl drove this point home with me. When we were preparing the proposal to make the electron-ion crossed beam measurements, only one other group in the world had succeeded in making such a machine work, that of Ken Dolder and Mike Harrison at Harwell Laboratories in the United Kingdom. They had published one paper on electron ionization of He+, but I thought that our proposed machine had some design advantages that would serve us well. One year into my construction phase, Earl told me that he had learned that Dolder had moved to Newcastle from Harwell and was initiating a study of the alkali ion reactions that would comprise my Thesis. He further noted that Dolder was having difﬁculty making intense beams of alkali cations and that my alkali ion source was clearly superior. He then told me that he hoped that I would be willing to send Dolder drawings for my thermionic ion source, and send him samples of the zeolites that were the ion emitters. He told me that such cooperation was what science was really about. It was with considerable uncertainty and trepidation that I complied with his request, for I feared that Dolder would now complete his measurements before I completed mine. As these measurements were intended to constitute the entirety of my Ph.D. Thesis, I was pretty nervous. As it turned out, the difﬁculties associated with Dolder’s relocation were even greater than expected, and our results were published two years ahead of him. The obvious lesson has really stuck with me, and speaks volumes about Earl.
About midway through my time in graduate school, Earl told me about a new type of institute that had just started as a partnership between the National Bureau of Standards (NBS) and the University of Colorado. The institute was called JILA, and it was associated with the Astrophysics, Aerospace Engineering, Chemistry, and Physics Departments at the university. After reading a bit about JILA, I decided that I would like to take a postdoctoral position there, working with one of the JILA founders, Lewis Branscomb. This actually happened, and I was scheduled to arrive at the same time as another newly minted Ph.D., Dick Zare. Dick planned to go to JILA for a postdoctoral position working with Gordon Dunn on photodissociation of ions. I had already heard of Dick and was looking forward to interacting with him. Fate intervened in the form of my obligation to the US Army, and my arrival at JILA was delayed 3.5 years, until August 1968. By then, Dick had completed his short JILA postdoctoral position, become a faculty member at MIT, returned to JILA as a faculty member in Chemistry and Physics, and decided to go to Columbia as a named Professor. The result was that Dick and I overlapped at Colorado for only a short period. Nevertheless, Dick became a wonderful colleague, advisor, and great friend. Virtually every night of the week, he and I would be the last two persons remaining in the JILA building. The instrument shops were locked at night, but, as a faculty member, Dick had keys that opened all doors. A long-lasting bond was formed in that empty building.
Three months after I arrived in JILA, it was announced that Lew Branscomb would leave JILA and become the Director of NBS in Washington. This was not a complete surprise, as I knew of several universities (including Georgia Tech) that were considering him for President. When Lew left, I stayed on as the senior person in his group of two. This gave me a wonderful opportunity to develop independence and to move from the really hard planned experiment to a much easier experiment using Peter Sorokin’s new device, a ﬂashlamp-pumped tunable dye laser. Boulder colleagues Jan Hall, Don Jennings, and Art Schmeltekopf were unbelievably generous with their knowledge and designs; in a matter of a couple of weeks, we had the ﬁrst high-resolution tunable-laser photodetachment apparatus producing results. With this background, I was very fortunate that the Department of Chemistry at the University of Colorado offered me a tenure track position. I very happily accepted the offer. It is clear that several people, including Dick Zare, Eldon Ferguson, and some others, had played a role in convincing the Department of Chemistry to hire an electrical engineer. I joined the faculty in August 1970, and my long-time colleague and friend Casey Hynes arrived the following January.
As a new faculty member, I was totally absorbed in work, and Aileen decided that this was not the life she had planned to live. Our marriage ended in 1971. In the late 1970s, however, something happened that I thought would never happen. I met someone who was as dedicated to her work as I was to mine. Moreover, she viewed my ridiculous behavior as almost admirable. We were married on July 31, 1979, and Kitty Edwards has been my constant support. Without her in my life, so many important things would never have happened.
I have been exceptionally fortunate to have worked with an outstanding group of students, postdoctoral associates, and Colorado colleagues. Our experiences have been further enriched by the large number of you who have joined with us, visiting from other universities, or collaborating from afar. I cannot acknowledge the essential contributions made by all of you whose names appear at the end of this Introduction, nor can I bear to omit any of you. Given this unsolvable dilemma, I give up and simply give explicit recognition to those of you who are “Colorado” locals. Bill Reinhardt and Steve Leone stand out as early and vital colleagues who played key roles in shaping physical chemistry at Colorado and JILA. Their departures from Colorado left a gaping hole in our programs. Fortunately, outstanding scientists from their groups joined the Chemistry/ JILA faculty: Barney Ellison, David Nesbitt, and Rex Skodje. All of these people have been and remain wonderful friends, collaborators, and colleagues. Veronica Bierbaum has been a vital collaborator for many years, and has truly enriched our science. Robert Parson has provided theoretical support, intellectual guidance, and joint students to us, and his contributions have been truly essential as we have become involved with larger cluster anions. Chuck DePuy has been an invaluable collaborator and chemical guide; he has forgotten more chemistry that I ever knew, and, as best I can tell, he forgets nothing. Veronica Vaida was always available to offer advice and valuable insights. Ralph Jimenez tries hard, but unsuccessfully, to educate me on the latest ultrafast laser technologies. Finally, I note that the newest Colorado physical chemist, Mathias Weber almost completes the circle. Mathias received his Ph.D. at Kaiserslautern with my ﬁrst postdoctoral associate, Hartmut Hotop, had a postdoctoral appointment with Mark Johnson at Yale, and then joined the Chemistry Department and JILA here in Boulder.
A fair amount of my time has been involved with scientists in JILA with whom I have had no formal collaborations, but who are always there to listen to ideas, to loan equipment, to offer thoughtful suggestions, and to be concerned with the health of the Institute. I especially note the important roles played by Jinks Cooper, Carl Wieman, Dick McCray, Eric Cornell, Debbie Jin, Jun Ye, Judah Levine, and Jan Hall.
Any recognition of important roles in shaping my path would be dramatically incomplete without again reiterating the crucial role of my wife Kitty Edwards in everything I do. Her support, help, thoughtful advice, and encouragement are boundless.
This autobiography originally appeared in the Journal of Physical Chemistry A on January 28, 2010.
References and Notes
(1) Muller, E. W. Sci. Am. 1952, 186, 58–63.
(2) Belser, R. B.; Hicklin, W. H. ReV. Sci. Instrum. 1956, 27, 293–96.
(3) Hotop, H.; Lineberger, W. C. J. Chem. Phys. 1973, 58, 2379–87.
(4) Leopold, D. G.; Ho, J.; Lineberger, W. C. J. Chem. Phys. 1987, 86, 1715–26.