Russell M. Pitzer

Russell Mosher Pitzer (born May 10, 1938) is an American theoretical chemist and educator.

He was born in Berkeley, California and attended public schools in this and the Washington, D.C. area.

He received his B.S. in chemistry in 1959 from the California Institute of Technology, his A.M. in physics from Harvard University in 1963, and his Ph.D. in chemical physics from Harvard University in 1963.

At Harvard, Pitzer worked with William N. Lipscomb, Jr. in cooperation with the research group of John C. Slater at M.I.T. to develop computer programs to use Slater orbitals to produce self-consistent field (SCF) molecular orbitals.

The ethane barrier (see diagram at right) was first calculated accurately by Pitzer and Lipscomb using Hartree Fock Self-Consistent Field (SCF) theory. Ethane gives a classic, simple example of such a rotational barrier, the minimum energy to produce a 360-degree bond rotation of a molecular substructure. The three hydrogens at each end are free to pinwheel about the central carbon-carbon bond, provided that there is sufficient energy to overcome the barrier of the carbon-hydrogen bonds at each end of the molecule bumping into each other by way of overlap (exchange) repulsion.

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