Felix T. Smith
Emeritus Physicist
Molecular Physics Laboratory

Felix Smith obtained his Ph. D. at Harvard in 1956 in Physical Chemistry with a thesis on a problem in chemical kinetics under George Kistiakowsky. He then joined SRI and was the lead theorist in the Molecular Physics Laboratory (MPL) until he retired in 1981, having served also as Director of the Laboratory for a number of years.

In the American Physical Society he has been active in the Division of Atomic, Molecular and Optical Physics, with long service on its Executive Committee and a term as its Chair in 1975. Internationally he has served on the General Committee of the International Conferences on the Physics of Electronic and Atomic Collisions, and was its Chair between 1975 and 1977. He is a Fellow of the APS and of AAAS.

Felix’s research contributions have ranged from fundamental quantum collision theory (scattering matrix and collision lifetimes; diabatic and adiabatic states in atomic and molecular collisions) through problems in chemical kinetics and atomic and ionic scattering, with practical applications to calculations and data analysis in specific systems. With Don Lorents, Jim Peterson and Charles Cook, he joined in building the strong theoretical and experimental collaboration in atomic, ionic and molecular collisions that has made SRI’s Molecular Physics Laboratory one of the world’s leading centers in atomic and molecular physics.

Felix’s current research program centers on improving the theoretical understanding of the transition between low-energy atomic and molecular systems and their behavior at relativistic energies. It is based on the recognition of a great discontinuity between the theoretical tools available in the two limiting regions, while the wide range of experimental information characteristically changes with smooth continuity through the full span of velocity or energy. His studies have led to the recommendation that Special Relativity should be modified so that its flat Minkowski space-time is generalized to a universe with an expanding, negatively curved position space. The new theory suggests also that the speed of light is not quite constant, but has been decreasing since the Big Bang. This change is very slow, less than one part in 1010 per year, but it might be within the reach of a sophisticated experimental measurement.

The new theory provides an answer to the original problem of calculational tools, a new approach to both the Schrödinger equation and the Dirac equation that will improve the bridge between them in the intermediate energy region. It also has many other new implications, and will open up new areas for investigation in the future.

F.T. Smith, Hamiltonian symmetry in special relativity: Relativity in expanding hyperbolic space, Ann. Fond. Louis de Broglie 30(2), 179–244 (2005).