These excerpts were brought together by Slater from his files, at the request of Dr. Leon Rosenfeld, to document Slater's visit to Copenhagen, and Bohr's Lab. In general, the letters concern quantum physics.

These contain a few notes and memoranda by Van Vleck, but the bulk of the collection is letters to and from him. Correspondents include Raymond T. Birge, Gerhard H. Dieke, Paul A. M. Dirac, Edwin C. Kemble, and Robert S. Mulliken.

This collection includes numerous Darwin writings, in manuscript and typescript, as well as letters to him from Niels Bohr, Max Born, M. Frenkel, Oskar Klein, J. E. Littlewood, H. Moseley, H. R. Robinson. The writings include such topics as magnetic storms, atom mechanics, and wave theory. There is also a copy of a paper in Darwin's hand by Henri Poincaré, "On the theory of Quanta" (published in Journal de Physique, 1912).

These are copies of material, mainly letters, not filmed for the Archive for the History of Quantum Physics (see PAAV86-A21). There is an interesting letter from Charle G. Darwin (1932) referring to Paul Ehrenfest, letters about the state of physics at Northwestern University from R. A. Fisher and B. J. Spence, and a letter by Hermann Weyl outlining a talk he was to give in Boston in December 1928.

John Archibald Wheeler (1911-2008) was a leading theoretical physicist of the twentieth century, contributing particularly to the fields of general relativity, gravitation, and quantum mechanics. Wheeler was a pioneer in the study of black holes, celestial phenomena which he named. (He had a penchant for creating new terms in physics, and is credited with naming other phenomena such as geons, wormholes, and quantum foam.) Wheeler is also known for his work in atomic and nuclear physics. In 1939, he and Niels Bohr co-authored a paper that gave the basis for recognizing that Uranium 235 and Plutonium 239 are highly fissile, a milestone in the understanding of atomic energy. Wheeler believed in the importance of public service, assisting in the U.S. war effort to develop the atomic and hydrogen bombs, and served as a scientific advisor to numerous government agencies. During a prolific academic career that spanned seventy years, Wheeler taught physics to thousands of undergraduate students at Princeton University and the University of Texas, and mentored more than fifty Ph.D. students. The Wheeler Papers provide an extensive look into the expansive career of John Archibald Wheeler, the pioneering and award-winning theoretical physicist. Comprised of 150 linear feet, this large collection contains a wide array of materials including correspondence, subject files, manuscripts by Wheeler, papers by colleagues and students, research notes and notebooks, photographs, awards, and audiovisual materials. The collection provides much insight in to Wheeler's lengthy career as a scientist, scholar, and teacher. The bulk of the material is from the 1950s to the 1990s and covers the wide scope of his professional endeavors, from his teaching at Princeton University and the University of Texas, to his many publications, to his consultation work with government agencies, industry, and atomic energy projects, to his numerous public talks and lectures.

The physicist W.F.G. Swann was a pioneer in high energy physics and the study of cosmic rays. Climbing the academic ranks from the University of Sheffield to the Universities of Minnesota, Chicago, and Yale, Swann was selected as the first director of the Bartol Research Foundation of the Franklin Institute in 1927, and remained there until his retirement in 1959. An able administrator and excellent mentor, he was best known for his popular work on the new physics, The Architecture of the Universe (1934) and for his research on cosmic rays. Avocationally, he was an accomplished cellist and in addition to performing, he helped organize and support the Swarthmore Symphony Orchestra and other local groups. He died at his home in Swarthmore in 1962. The Swann Papers consist of 41 linear feet of correspondence, class notes, lectures, and photographs documenting Swann's career at the Bartol Research Foundation from 1927 until the end of his life. The collection is wide ranging, touching on atmospheric electricity, particle acceleration, atomic bomb defense, atomic energy, electrets, electrodynamics, magnetism, music, quantum theory, radiation, relativity and Einstein, science and civilization, stratospheric flights (by balloon and airplane), thermodynamics, psychic science, and wave mechanics. It is particularly rich for study of the history of cosmic ray research and the Bartol Institute, and for study of the popularization of modern physical sciences.

Edward Uhler Condon was a theoretical physicist at Princeton University and Westinghouse Laboratories who later served as director of the National Bureau of Standards (1945-1951), and as the director of research and development (1951-1954) and consulting physicist (1954-1974) at Corning Glass Works. The Condon Papers includes correspondence, notebooks, writings, photographs, and other materials concerning Condon's education, teaching, and his government, industrial, and academic.

After receiving his doctorate from Harvard in 1923, the physicist John Clarke Slater did postgraduate work at Cambridge University and on the continent working n quantum theory with both Niels Bohr and Werner Heisenberg. Slater was appointed to the head of the department of physics at MIT in 1930, which he and Karl Compton worked effectively to transform into one of international stature. His own work on the electromagnetic theory of microwaves was fundamental to the development of radar systems. During the Second World War, he was affiliated with the radiation laboratory and after he helped found the solid state and molecular theory group, the interdisciplinary Center for Materials Science and Engineering, the Research Laboratory of Electronics, and the Laboratory for Nuclear Science. After his retirement from MIT in 1966, Slater moved to the University of Florida, remaining active until his death in 1976. The Slater Papers contains a wealth of information on the development of physics at MIT, as well as Slater's post-1966 work at the University of Florida. There are about 133 (7 linear ft.) research notebooks, 1944-1976, and a long series (30 linear ft.) of folders, containing lectures, scientific notes, drafts of manuscripts and papers, correspondence during his collaboration with the Los Alamos Labs, 1966-1970, and extensive correspondence relating to the National Academy of Science. Information about American-Swedish exchange in quantum science is located in the correspondence with Per-Olov Löwdin.