Ronald G. W. Norrish Biography

Ronald George Wreyford Norrish was born in 1897, in Cambridge, England. The son of Amy and Herbert Norrish, his undergraduate studies at Cambridge University were interrupted by service in France during World War I. After the war he resumed his studies and continued on at Cambridge, earning a Ph.D. in chemistry in 1924. Norrish married Anne Smith two years later; the couple had twin daughters. He served for the rest of his academic and research life at Cambridge University until his retirement in 1965. Norrish died at Cambridge in 1978.

Norrish's early work at Cambridge involved the photochemistry of rather simple compounds, such as ketones, aldehydes, and nitrogen peroxide. He discovered that light breaks down these compounds in one of two directions, creating either stable molecules or unstable "free radicals," which are molecules that have unpaired electrons. As a corollary to this work, Norrish and his laboratory also began studying chemical chain reactions. Working with M. Ritchie, Norrish was able to describe the process by which hydrogen and chlorine react when initiated by light. Studies of other chain reactions led Norrish and his fellow workers to a study of hydrocarbon combustion, building on Nikolai N. Semenov' s work in branching chain reactions to describe the means by which methane and ethylene are combusted. They discovered that formaldehyde formation is a necessary intermediate step in such a chain reaction.

Norrish also conducted an investigation into the mechanics of polymerization, primarily in vinyl compounds. It was Norrish who coined the term 'gel effect' to describe the final slowing-down stages of polymerization as a solution undergoing the process becomes increasingly semi-fluid or viscous. With the advent of World War II, Norrish's laboratory work increasingly involved military projects, such as research into gun-flash suppression. Norrish became chairman of the Incendiary Projectiles Committee during this period and also assisted in the development of incendiary devices.

After the war, Norrish worked with Porter to pioneer the study of flash-photolysis. This involved the measurement of very fast chemical reactions while exposing the substance to extremely strong and short blasts of light. Unstable molecules turned into free radicals, thus resulting in a dissociative reaction. Intermediate stages and products of such fast chemical reactions were then gauged by use of spectrographic analysis--the illumination by weaker flashes of light following at millisecond intervals upon the initial flash. Such analysis went a long way toward proving intermediate stages of reactions which had been, until the Norrish-Porter work, only theoretical.

Norrish and Porter continued their research together from 1949 to 1965, perfecting their technique to allow analysis of short-lived intermediate compounds down to a thousandth of a millionth of a second. They published numerous articles and opened new vistas of research in fast reactions. For such work, Norrish and Porter shared the 1967 Nobel Prize for Chemistry with Eigen, who was doing similar work.