This lecture honors Prof. Samuel I. Weissman, Washington University faculty member from 1946 until his death in 2007. Sam was born in Chicago in 1912 and obtained both B.S. (1933) and Ph.D. (1938) degrees from the University of Chicago. After post-doctoral work at Chicago, he joined G. N. Lewis’s lab in 1941 at the University of California in Berkeley as a National Research Council post-doctoral fellow. There he did outstanding work in the optical spectroscopy of rare earth ions and on the mechanism of phosphorescence (with David Lipkin). With the start of WW II, Weissman joined the Radiation Laboratory to work on isotope separation techniques. In 1943, he was recruited to Los Alamos, where he worked on the implosion mechanism needed to detonate the Nagasaki bomb and on the application of a protective coating to prevent corrosion of the plutonium core.
In 1946, Weissman moved to the WU faculty with five of his Los Alamos colleagues, where he continued outstanding researches into optical spectroscopy, but soon turned to the brand new field of magnetic resonance in which he was to become a renowned pioneer and world-class expert. Weissman’s attention focused on electron spin resonance (ESR). His pathbreaking studies were initially carried out using home-built spectrometers designed and fabricated by Jack Townsend of the WU Department of Physics. Contributions of the Weissman Lab over the subsequent years include: the first observation of hyperfine splitting of the ESR spectral lines, which is caused by interaction of the spin of the unpaired electron with those of the nuclei in the molecule; showing that the unpaired electron is distributed over the entire molecule; demonstration (with David Lipkin) that metallic sodium reacts with aromatic compounds to produce anions with one unpaired electron (aromatic “free radicals”); determination from ESR spectra of rates of electron transfer; and recognition that the photo-excited triplet state has strong electron spin polarization, even at room temperature, and development of means to detect and characterize it (with Tom Lin and David Sloop). A scientist to the core, Weissman did creative research until virtually his last days at the age of 95.
Weissman’s formidable intellect was embedded in a personality that could not have been less intimidating, and he inspired and educated student and colleague alike in innumerable office as well as classroom blackboard sessions. You gained insight, but also had fun. Sam Weissman was a consummate and folksy raconteur, and the cast of characters in his tales of old days in the Chicago ghetto of the 1920s and 1930s leaped to the imagination as vividly as any in Dickens.