By T. Daniel Crawford
Fritz's father had a profound impact on his life, not the least being his devotion to his family and the strong work ethic he instilled in all three of his children. He was a native of Grand Rapids and a childhood friend to a neighbour who would eventually become president, Gerald Ford. Fritz's father completed his undergraduate studies at the depths of the Great Depression, and so had to find whatever job he could muster. His belief in the virtue of hard work paid off, though, and he gradually worked his way up in the American Seating Company from sweeping the factory floor to a job that allowed him to take advantage of his engineering degree: designing seats for US combat planes during World War II. By the time he took early retirement in 1968, he had advanced through the company to become one of its highest-ranking executives.
Although Fritz's family moved several times in his first 13 years of life — from Michigan to New York to California and finally back to Michigan — his family was very close and his home life strong. His introduction to the working world came in the form of a newspaper route at the tender age of 10, followed two years later by a part-time job at a neighbourhood grocery store for a whopping (for that time) $0.75/hour. In the summer of 1961, following his junior year at East Grand Rapids High School, he got his first full-time job working for the State Plating Company on an assembly line — and a nice pay raise to $1.50/hour. However, the extreme heat of the factory and the chemicals involved in the electroplating process eventually took their toll on his health, and he broke out in a terrible rash all over his body. Fritz's doctor thus ‘forced’ him to quit this lucrative job and spend the remainder of the summer swimming in Fisk Lake.
Fritz met his future bride, Karen Rasmussen, during his junior year of high school. Karen was one year behind him, and they dated a few times, but remained little more than friends until he was home for the summer after his second year of college. Fritz was taking a summer course in German at nearby Calvin College when Karen's father hired him to tutor her brother in calculus. In Fritz's mind, this was ‘the opportunity of a lifetime’ and he took full advantage, staying late every evening after his tutoring duties were complete to get to know her better.
When it was time to depart for college, Fritz had his choice between Stanford University and MIT. Although his years as a child in Menlo Park, California, gave him a strong attraction to nearby Stanford, his father strongly encouraged him towards the engineering Mecca of Cambridge. Fritz found the first year of mathematics, physics, and chemistry courses daunting because of the heavy competition, but he soon came into his own and emerged as one of the best in his classes. He initially chose to major in chemical engineering, but thought the problems assigned by his instructors were too ‘trial and error’. He yearned for a more fundamental science, and soon decided to switch to chemical physics (a major no longer offered at MIT because of complaints from chemistry departments at other schools that MIT's graduates only seemed to know the ‘physics’ rather than the ‘chemical’ half of their degrees).
Fritz's true scientific calling was perhaps first revealed in George Whitesides's organic chemistry course. Fritz almost demolished a fume hood with a failed aniline experiment. He recalled Professor Whitesides's comments after surveying the destruction, "The damage here is far in excess of the lab fee you paid. Have you ever considered theoretical chemistry?"
While Fritz was thus convinced that synthetic organic chemistry was not his forté, he still had an attraction to experiment, namely spectroscopy, which he once referred to as ‘that glorious crescendo of applied quantum mechanics’. He worked hard in courses taught by a roster of scientists that today's younger generation of quantum chemists would leap at a chance to meet: John C. Slater, electronic structure theory; F. Albert Cotton, chemical group theory; and Richard Lord, molecular spectroscopy. However, providence seemed to direct him along a different path once again because he couldn't raise the courage to ask Professor Lord for a position in the MIT spectroscopy laboratory. His academic adviser, Professor Walter Thorson, then suggested he consider an option that would become his lifelong road: a project in quantum chemistry in Thorson's own group.
Professor Thorson assigned Fritz a senior thesis project focused on the electronic structure of the H8 cube, which he set out to describe using both molecular orbital (MO) and valence bond (VB) theories. While the former was relatively straightforward, the latter proved to be a significant challenge, about which Fritz later said, ‘If God wanted people to work with non-orthogonal orbitals, He surely would have made the resulting Hamiltonian matrix elements immensely easier to evaluate!’
Apart from his studies, Fritz also had a strong interest in sports, and he played for MIT's hockey team for three years. The competition was fierce, with a schedule that included hockey-powerhouse schools like New Hampshire and Vermont that featured a number of future stars of the National Hockey League. ‘It was just frightening to be out there,’ Fritz said recently. ‘Nobody was saying ‘let me in coach’.’ His team endured, but the pinnacle of its performance was an 0–16 record in his second year of play, safe in the knowledge that at least they understood calculus if not the crease.
A week before final exams in his junior year at MIT, Fritz found himself in the MIT infirmary with a quickly rising fever. After a week of antibiotics, his doctor finally took a chest X-ray and diagnosed him with a serious bout of pneumonia. Fortunately (and somewhat amazingly) all of his professors let him off the hook from his exams and gave him (well deserved) As. He spent the first few weeks of summer recovering from his illness, and then spent time following Karen around Europe — to Denmark, Holland, and elsewhere in Europe — until they were finally engaged to be married.
Fritz and Karen were married on 2 September 1966, and spent their honeymoon driving from Grand Rapids to Palo Alto. Fritz had received a National Defense Education Act Fellowship that would pay for his PhD studies, and his lifelong attraction to California had resulted in his decision to pursue a PhD in chemistry at Stanford. The decision was made that much easier because Karen, who had been majoring in art history at Wells College in upstate New York, had been offered the opportunity to complete her studies at Stanford, and because Fritz was intrigued by Prof. Frank Harris's research in quantum chemistry. Fritz also considered working with Harden McConnell in the area of biological membranes, but the lure of ab initio electronic structure theory was too great, and he joined Harris's group soon after his arrival on campus.
Karen completed her degree in art history in their first year in Palo Alto and then moved on to pursue a teaching credential at San Jose State University. Consistent with their upbringings, Fritz and Karen both worked 80 hours per week, and spent all their remaining time together. Professor Harris had a relatively small group at Stanford, consisting of Uzi Kaldor (a postdoc at the time and now an emeritus professor at Tel Aviv University) and a few graduate students, including Fritz. His thesis committee included Harris, John Brauman, and Leonard Schiff, the author of the venerated text on quantum mechanics.
Fritz's research focused primarily on the electronic structure of first-row atoms, and he found inspiration from a variety of sources. In January of 1968, he attended a Winter School on Sanibel Island, organized by Per-Olov Löwdin, founder of the University of Florida's Quantum Theory Project. There he met his good friend Jack Simons, and two now-departed friends, Bowen Liu and Peter Kollmann. He enjoyed magnificent lectures by Löwdin, Ruben Pauncz and numerous other famous scientists. In June of that same year he gave a short talk at a Gordon Conference on theoretical chemistry, organized by 1998 Nobel Prize winner John Pople at Crystal Mountain, Washington. Fritz was supremely impressed by Pople, and, although to Fritz he seemed nearly unapproachable at the time, they became good friends within a few years.
Professor Harris offered his students direction and training when needed, but also gave them free rein when it was clear that they could be independently productive. And Fritz was certainly productive. His intense workweek resulted in an astonishing 12 publications (including seven in Physical Review and Physical Review Letters) in an equally astonishing 2.5 years before defending his dissertation.
Following Fritz's brief and stellar graduate career, Frank Harris (who had moved to the University of Utah) and John Brauman recommended the young Dr. Schaefer for faculty positions at MIT and Berkeley, as well as a junior fellowship (an independent postdoc, comparable to a European habilitation) at Harvard University. Although he wasn't chosen for the Harvard or MIT positions, he was offered the job he wanted most: an assistant professorship at nearby Berkeley, and he arrived on campus in June of 1969, just a few days after his 25th birthday. His research start-up costs were paid by the Lawrence Radiation Laboratory (now with the more palatable name Lawrence Berkeley National Laboratory) and consisted primarily of 100 hours per year on the LRL's Control Data Corporation (CDC) 6600 mainframe computer, time that ‘was worth real money back then’, according to Fritz.
Fritz and Karen took up residence in Orinda, just eight miles from campus. Karen, who had completed her teaching credential at San Jose State, landed a job as a fourth-grade teacher in nearby Moraga, and the two of them continued their intense 80 hour work weeks. Fritz was joined at Berkeley at the same time by another theoretical chemist, William H. Miller, who had just completed a coveted junior fellowship at Harvard. Fritz recruited three graduate students in his first year, one of whom (Stephen O'Neil) completed the PhD preliminary examinations. Additionally, he began one of his most fruitful collaborations in late 1969, when he met Dr Charles Bender, who had been recruited to the area by another of Fritz's collaborators, Dr Stephen Rothenberg of the University Computing Company (UCC) in Palo Alto.
Fritz and his group circa 1972: (left to right) HFS, Steve O'Neil, Charlie Bender, Gretchen Schwenzer, Barbara Garrison, Bob Hand, Peter Pearson, Dean Liskow, and David Yarkony. Fritz's 1969 red Chevy Suburban was large enough to transport the entire group.
UCC had its own UNIVAC 1108, and with such an important computing tool at their disposal, Fritz and Charlie started developing new programs for incorporating electron correlation into polyatomic wave functions. The structure of the 3B1 ground state of methylene was their first and perhaps most famous target. The conventional wisdom of the time was that the molecule was linear — wisdom that originated with the work of Canadian spectroscopist Gerhard Herzberg. Indeed, Herzberg received the Nobel Prize in 1971 for his work on the spectroscopy of free radicals, including methylene, which even the Nobel presentation speech specifically described as ‘linear in its ground state 1.’
Fritz and Charlie disagreed with the status quo, however, and pursued what was later described as ‘by far the most elaborate calculation carried out to date on methylene, or indeed almost any molecule 2,’ namely a 408-term configuration interaction (CI) wave function using the UCC UNIVAC 1108. They concluded in a 1970 paper in the Journal of the American Chemical Society ‘that the CH2 ground state is nonlinear with a geometry close to r = 1.096 Å, θ = 135.1° 3.’ Fritz later described their prediction as ‘outrageous’ and ‘youthful brashness,’ which, if wrong, would probably have dashed his hopes for tenure. But electron spin resonance experiments carried out a few months later confirmed their result. Soon thereafter, Herzberg published a revision to the conventional wisdom 4, the Nobel committee's presentation speech notwithstanding. Needless to say, Fritz received tenure and promotion to associate professor in 1974.
A serious computer crisis began in 1972, arising partly from the growth of the group and concomitant demands from the LRL that the Schaefer group pay for its computing time on the CDC mainframe. Fritz and Bill Miller were thus inspired — with considerable blowback from the Berkeley computing committee — to submit a proposal to the National Science Foundation for the purchase of a computer for exclusive use by their two groups. This successful proposal, ‘Large Scale Scientific Computation via Minicomputer,’ led to the 1974 purchase of a Datacraft 6024/4 minicomputer, a machine with a massive 0.2 MB of memory. According to a biography published in 2004, ‘The 54 MB removable-pack disk drive was the size of a washing machine and sounded like one, too 5.’ Although the machine came with its own set of headaches, it was wildly successful and demonstrated that individual research groups could (and often should) seek their own, independent computing resources.
Fritz and Bill Miller celebrate the success of their new Datacraft 6024/4 minicomputer in early 1974.
Fritz's life went through a number of important transitions in the 1970s. First, after years of study and literal soul-searching, he became a Christian in 1973. Karen and Fritz also started their family at that time, beginning with their daughter, Charlotte in 1974, followed by Pierre (who tragically died in infancy in 1979), Theodore (1980), Rebecca (1984), and Caleb (1986). In January 1975, Fritz began what has become a life-long tradition of visits to Professor Leo Radom in Australia, to which he has travelled 20 times since. In September of 1979, Fritz moved to Austin, Texas as the inaugural director of the Institute for Theoretical Chemistry at the University of Texas. The position attracted him in part because of the promise of 25 hours per week on a new CDC Cyber 170/750 mainframe. In March prior to the move, Yukio Yamaguchi from Michael Dewar's lab in Austin joined the Schaefer group in Berkeley as a postdoc, only to be ‘shipped back to Texas’ six months later with the group's move southward. Dr Yamaguchi has remained with the Schaefer group as research associate ever since, to the great fortune of generations of Fritz's graduate students who have learned much from him over the years. The group's time in the Texas heat lasted only a year, however, as Fritz was enticed to return to Berkeley in 1980 in part because of the university's acquisition of a Harris Corporation 800 minicomputer for the sole use of the Miller and Schaefer labs.
Fritz remained amazingly prolific during his time at Berkeley, and his group continued its efforts in both chemical applications and new quantum chemical methods. They were at the centre of the development and implementation of the graphical unitary group approach (GUGA) to CI, analytical energy derivatives for Hartree–Fock, CI, and coupled cluster methods, the Z-vector technique for orbital and wave function response, and more. In addition to 375 papers, Fritz published two books during this period. The Electronic Structure of Atoms and Molecules: A Survey of Rigorous Quantum Mechanical Results appeared in 1972, and Quantum Chemistry: The Development of Ab Initio Methods in Molecular Electronic Structure Theory in 1984. The latter is a survey of 149 landmark papers in electronic structure theory — starting with Hylleraas's paper on the helium atom in 1928 — each with a brief commentary written by Fritz. Both books were well received by the theoretical chemistry community, and his 1984 book remains available from Dover Publications.
In 1987, life was moving fast for the Schaefers in Berkeley, and with their children rapidly approaching their teens, Fritz and Karen began considering options that would help to slow things down. Two years earlier, Fritz's long-time collaborator, Charlie Bender, had accepted a position as the director of the Advanced Computing Methods Center at the University of Georgia, and, in collaboration with the new university president, Dr Charles Knapp, he was able to engineer an offer to try to coax Fritz to move to Athens. Lou Allinger, the prominent computational chemist at UGA who developed the popular molecular mechanics methods recently recalled, ‘I thought they’d never be able to hire this guy. Georgia was out in the boondocks then, but Charlie Bender did it some how. I was amazed.’ In August 1987, Fritz became the Graham Perdue professor of chemistry and director of the new Center for Computational Quantum Chemistry (CCQC), timed perfectly with the arrival of the campus's new IBM 3090-200E mainframe (and a new, fruitful partnership with IBM).
Moving a group as large as Fritz's is naturally a complex operation, but he was undaunted. (In fact, Fritz even tried to convince Bill Miller to move his group to UGA at the same time.) Some of the more senior Schaefer students remained behind to complete their research, while others (Curt Janssen and Brenda Colgrove) finished their Berkeley degrees while in residence in Athens, and one more (Edward Seidl) transferred to become Fritz's first PhD student from the University of Georgia.
After Fritz had been in Georgia less than a month, he was invited to Savannah to speak before a University board. There he met Vince Dooley, the UGA athletic director and former coach of the Bulldogs football team. They developed a strong relationship thereafter, and Dooley was instrumental in helping to secure part of the funding for the ‘Computational Chemistry Annex,’ a beautiful facility constructed in 1998 specifically to house UGA's growing theoretical chemistry community.
Fritz's group continued to expand and his science to blossom after his move to Georgia. He and his group maintained development of advanced quantum chemical methods, including CI and coupled cluster methods through the vehicle of his group's computer code, PSI (formerly known as the BERKELEY programs). In addition, he has served as a board member of and steward to the Q-Chem company since 1998. A theme of his research, as evident from the methylene saga, has always been the use of state-of-the-art quantum chemical models to explain and often overturn experimental conclusions. At UGA, he thus expanded his efforts to offer insights into a variety of chemical phenomena, ranging from the spectroscopy of small molecules to the structure and electron affinities of DNA nucleosides. So far, he has published more than 1200 papers (nearly 900 since his move to Athens), and produced over 90 PhDs (more than 60 at UGA).