John C. Slater

Slater's papers were bequeathed to the American Philosophical Society by his widow, Rose Mooney Slater, in 1980 and 1982. In August 2003, Alfred Switendick donated a collection of Quarterly Reports of the MIT Solid State and Molecular Theory Group (SSMTG), dating from 1951 to 1965. These are available in several major research libraries.

At the University of Florida (Gainesville) where the retirement age was 70, Slater was able to enjoy another five years of active research and publication as a Research Professor in the Quantum Theory Project (QTP). In 1975, in his scientific autobiography, he wrote: ""The Florida Physics Department was a congenial one, with main emphasis on solid state physics, statistical physics and related fields. It reminded me of the MIT department in the days when I had been department head there. It was a far cry from the MIT Physics Department which I was leaving; by then it had been literally captured by the nuclear theorists." Slater published to the end of his life: his final journal paper, published with John Connolly in 1976, was on a novel approach to molecular orbital theory.

Slater was nominated for the Nobel Prize, in both physics and chemistry, numerous times, and he received the National Medal of Science in 1970. In 1964, Slater and his then-92 year-old father, who had headed the Department of English at the University of Rochester many years earlier, were awarded honorary degrees by that university. Slater's name is part of the terms Bohr-Kramers-Slater theory, Slater determinant and Slater orbital.

The Center was set up, in accordance with Slater's plans. It "supported research and teaching in Metallurgy and Materials Science, Electrical Engineering, Physics, Chemistry and Chemical Engineering", and preserved MIT as a focus for work in solid state physics. By 1967, two years after Slater left, the MIT Physics Department "had a very, very small commitment to condensed matter physics" because it was so "heavily into high energy physics." But in the same year, the CMSE staff included 55 professors and 179 graduate students. The Center continues to flourish in the 21st century.

Prof. Slater was also Committee Member for Dr. Ravi Sharma's Ph.D.(1966, U of Florida Gainesville) and for many such committees. He and Rose said to Ravi that he had lost his books and research papers when the truck carrying his belongings overturned while moving from MIT to Gainesville.

The Cooperative Computing Laboratory (CCL) was used, in its first year by some 400 faculty, students and staff. These included (1) members of the SSMTG and the CCL running quantum mechanical calculations and non-numeric applications directed by Slater, Koster, Wood and Barnett, (2) the computer-aided design team of Ross, Coons and Mann, (3) members of the Laboratory for Nuclear Science, (4) Charney and Phillips in theoretical meteorology, and (5) Simpson and Madden in geophysics (from 1964 President's report, p. 336-337).

In the 1962 President's Report, Jay Stratton wrote (on p. 17) "A faculty committee under the chairmanship of Professor John C. Slater has taken primary responsibility for planning the facilities in the new Center for Materials. These include a new Cooperative Computing Laboratory completed this year and equipped with an I.B.M. 709 Computer".

Solid state work progressed more rapidly at first in the SSMTG, with contributions over the first few years by George Koster, John Wood, Arthur Freeman and Leonard Mattheis. Molecular and atomic calculations also flourished in the hands of Fernando J. Corbató, Lee Allen and Alvin Meckler. This initial work followed lines largely set by Slater. Michael Barnett came in 1958. He and John Wood were given faculty appointments. Robert Nesbet, Brian Sutcliffe, Malcolm Harrison and Levente Szasz brought in a variety of further approaches to molecular and atomic problems. Jens Dahl, Alfred Switendick, Jules Moskowitz, Donald Merrifield and Russell Pitzer did further work on molecules, and Fred Quelle on solids.

In 1950, Slater founded the Solid State and Molecular Theory Group (SSMTG) within the Physics Department. The following year, he resigned the chairmanship of the department and spent a year at the Brookhaven National Laboratory of the Atomic Energy Commission. He was appointed Institute Professor of Physics and continued to direct work in the SSMTG until he retired from MIT in 1965, at the mandatory retirement age of 65.

Slater' publications during the war and the post-war recovery include a book and papers on microwave transmission and microwave electronics, linear accelerators, cryogenics, and, with Francis Bitter and several other colleagues, superconductors, These publications credit the many other scientists, mathematicians and engineers who participated. Among these, George H. Vineyard received his Ph.D. with Slater in 1943 for a study of space charge in the cavity magnetron. Later, he became Director of the Brookhaven National Laboratory and President of the American Physical Society. The work of the Radiation Laboratory paralleled research at the Telecommunications Research Establishment in England and the groups maintained a productive liaison.

From the memoir by Philip Morse: "He contributed significantly to the start of the quantum revolution in physics; he was one of the very few American-trained physicists to do so. He was exceptional in that he persisted in exploring atomic, molecular and solid state physics, while many of his peers were coerced by war, or tempted by novelty, to divert to nuclear mysteries. Not least, his texts and his lectures contributed materially to the rise of the illustrious American generation of physicists of the 1940s and 1950s."

In 1930, Karl Compton, the President of MIT, appointed Slater as Chairman of the MIT Department of Physics. He recast the undergraduate physics curriculum, wrote 14 books between 1933 and 1968, and built a department of major international prestige. During World War II, his work on microwave transmission, done partly at the Bell Laboratories and in association with the MIT Radiation Laboratory, was of major importance in the development of radar.

Throughout his Chairmanship, Slater taught, wrote books, produced ideas of major scientific importance, and interacted with colleagues throughout the local, national and international scientific communities. At the personal level, Morse states: "Through most of (the 1930s) he looked more like an undergraduate than a department head ... he could render his guests weak with laughter simply by counting ... in Danish." Much later, S.B. Trickey wrote "While I got to know him reasonably well, I was never able to call J.C. Slater by his given name. His seeming aloofness turned out more to be shyness."

In 1926, he had married Helen Frankenfeld. Their three children (Louise Chapin, John Frederick, and Clarke Rothwell) all followed academic careers. Slater was divorced and in 1954 he married Rose Mooney, a physicist and crystallographer, who moved to Florida with him in 1965.

Slater joined the Harvard faculty on his return from Europe in 1925, then moved to MIT in 1930. His research papers covered many topics. A year by year selection, up to his switch to work relating to radar includes:

In his memoir, Morse wrote "In addition to other notable papers ... on ... Hartree's self-consistent field, the quantum mechanical derivation of the Rydberg constant, and the best values of atomic shielding constants, he wrote a seminal paper on directing valency " (what became known, later, as linear combination of atomic orbitals). In further comments, John Van Vleck pays particular attention to (1) the 1925 study of the spectra of hydrogen and ionized helium, that J.V.V. considers one sentence short of proposing electron spin (which would have led to sharing a Nobel prize), and (2) what J.V.V. regards as Slater's greatest paper, that introduced the mathematical object now called the Slater determinant. "These were some of the achievements (that led to his) election to the National Academy ... at ... thirty-one. He played a key role in lifting American theoretical physics to high international standing." Slater's doctoral students, during this time, included Nathan Rosen Ph.D. in 1932 for a theoretical study of the hydrogen molecule, and William Shockley Ph.D. 1936 for an energy band structure of sodium chloride, who later received a Nobel Prize for the discovery of the transistor.

He was accepted into Harvard graduate school, with the choice of a fellowship or assistantship. He chose the assistantship, during which he worked for Percy W. Bridgman. He followed Bridgman's courses in fundamental physics and was introduced into the then-new quantum physics with the courses of E. C. Kemble. He completed the work for the Ph.D. in three years by publishing his (1924) paper Compressibility of the Alkali Halides, which embodied the thesis work he had done under Bridgman. His heart was in theory, and his first publication was not his doctor's thesis, but a note (1924) to Nature on Radiation and Atoms.

Returning in time to 1920, Slater had gone to Harvard to work for a Ph.D. with Percy Bridgman, who studied the behaviour of substances under very high pressures. Slater measured the compressibility of common salt and ten other alkali halides—compounds of lithium, sodium, potassium and rubidium, with fluorine, chlorine and bromine. He described the results as "exactly in accord with Bohr's recent views of the relation between electron structure and the periodic table". This brought Slater's observation concerning the mechanical properties of ionic crystals into line with the theory that Bohr had based on the spectroscopy of gaseous elements. He wrote the alkali halide paper in 1923, having "by the summer of 1922" been "thoroughly indoctrinated ... with quantum theory", in part by the courses of Edwin Kemble following a fascination with Bohr's work during his undergraduate days. In 1924, Slater went to Europe on a Harvard Sheldon Fellowship. After a brief stay at the University of Cambridge, he went on to the University of Copenhagen, where "he explained to Bohr and Kramers his idea (that was) a sort of forerunner of the duality principle, (hence) the celebrated paper" on the work that others dubbed the Bohr-Kramers-Slater (BKS) theory. "Slater suddenly became an internationally known name.". Interest in this "old-quantum-theory" paper subsided with the arrival of full quantum mechanics, but Philp M. Morse's biography states that "in recent years it has been recognized that the correct ideas in the article are those of Slater." Slater discusses his early life through the trip to Europe in a transcribed interview.

Slater's father, born in Virginia, who had been an undergraduate at Harvard, became head of the English Department at the University of Rochester, which would also be Slater's undergraduate alma mater. Slater's youthful interests were with things mechanical, chemical, and electrical. A family helper, a college girl, finally put a name (then little-known as a subject) to his set of interests: physics. When Slater entered the University of Rochester in 1917 he took physics courses and as a senior assisted in the physics laboratory and did his first independent research for a special honors thesis, a measurement of the dependence on pressure of the intensities of the Balmer lines of hydrogen.

John Clarke Slater (December 22, 1900 – July 25, 1976) was a noted American physicist who made major contributions to the theory of the electronic structure of atoms, molecules and solids. He also made major contributions to microwave electronics. He received a B.S. in Physics from the University of Rochester in 1920 and a Ph.D. in Physics from Harvard in 1923, then did post-doctoral work at the universities of Cambridge (briefly) and Copenhagen. On his return to the U.S. he joined the Physics Department at Harvard.