June 7, 1896-October 31, 1986

BY R. STEPHEN BERRY

ROBERT S. MULLIKEN WAS a quiet, soft-spoken man, yet so single-minded and determined in his devotion to understanding molecules that he came to be called “Mr. Molecule.” If any single person's ideas and teachings dominated the development of our understanding of molecular structure and spectra, it surely was Robert Mulliken. From the beginning of his career as an independent scientist in the mid-1920s until he published his last scientific papers in the early 1980s, he guided an entire field through his penetrating solutions of outstanding puzzles, his identification (or discovery) and analysis of the new major problems ripe for study, and his creation of a school —the Laboratory of Molecular Structure and Spectroscopy or LMSS at the University of Chicago, during its existence the most important center in the world for the study of molecules.

Robert's background led him naturally into academic science. He was born in Newburyport, Massachusetts, in a house built by his great-grandfather in about 1798. His father, Samuel Parsons Mulliken, was a professor of chemistry at MIT, which made him a daily commuter between Newburyport and Boston. Samuel Mulliken and his childhood friend and later MIT colleague Arthur A. Noyes were