Rudolph A. (Rudy) Marcus, Caltech's John G. Kirkwood and Arthur A. Noyes Professor of Chemistry, passed away on July 16, 2026. Marcus was a faculty member in Chemistry at Illinois from 1964 to 1978.
He was awarded the Nobel Prize in Chemistry in 1992 "for his contributions to the theory of electron transfer reactions in chemical systems". His theory, now known as Marcus theory, provides a thermodynamic and kinetic framework for describing one electron outer-sphere electron transfer reactions, such as those that operate in the biochemical processes of respiration and photosynthesis.
In Caltech's announcement of his passing, Caltech President Ray Jayawardhana said Marcus's career exemplified the beauty and reach of fundamental science, and he will be deeply missed by the Caltech community.
"He was a visionary scientist who transformed our understanding of chemical reactions at their most elementary level. By uncovering the elegant physical principles that govern electron transfer, he gave scientists the ability to predict and engineer one of nature's most basic processes. His pioneering work laid the conceptual foundations that continue to shape advances in clean energy, catalysis, electronics, and beyond."
According to Caltech, Marcus authored more than 500 publications over a span of nearly eight decades and maintained an active research laboratory at Caltech until his death.