Ronald G. W. Norrish Biography

The English chemist Ronald G. W. Norrish spent his academic life studying reaction kinetics, a discipline in chemistry concerned with rates of chemical reactions and factors influencing those rates. Norrish received the 1967 Nobel Prize for Chemistry--which he shared with a former student, George Porter, and German scientist Manfred Eigen --for his work in this realm. A pioneer researcher in flash photolysis (chemical reactions induced by intense bursts of light), Norrish developed a process which allowed minute intermediate stages of a chemical reaction to be measured and described. He also contributed to chemistry an understanding of chain reactions, combustion, and polymerization (the formation of large molecules from numerous smaller ones). Over his career, Norrish was awarded the Liversidge Medal of the Chemical Society and the Davy Medal of the Royal Society, both in 1958, and the Bernard Lewis Gold Medal from the Combustion Institute in 1964. In addition, he was a member of scientific academies in eight foreign countries.

Ronald George Wreyford Norrish was born on November 9, 1897, in Cambridge, England. The son of Amy and Herbert Norrish, he attended the Perse Grammar School and won a scholarship to study natural sciences at Emmanuel College in Cambridge University. Although Norrish entered Cambridge in 1915, World War I intervened and he served in France as a lieutenant in the Royal Field Artillery. Captured by the Germans in 1918, he spent a year in a prisoner of war camp before being repatriated. Norrish then returned to his academic career at Cambridge and finished his bachelor of science degree in chemistry by 1921.

Norrish studied for his doctorate under the renowned physical chemist E. K. Rideal, who directed him to investigations of chemical kinetics and photochemistry (the effect of light upon solutions of potassium permanganate). By 1924 he had earned his Ph.D. in chemistry, staying on at the university to become a fellow of Emmanuel College and then, in 1925, a demonstrator in chemistry. The following year Norrish married Anne Smith who was a lecturer at the University of Wales. They would eventually have twin daughters together.

Norrish served for the rest of his academic and research life at Cambridge University. He became the Humphrey Owen Jones Lecturer in Physical Chemistry in 1930, then seven years later, he was named professor of physical chemistry as well as the director of the department of physical chemistry. He retained this position until 1965, when he retired.

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 NikolaiN. 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 (although he employed a "relaxation technique," whereby small disturbances of equilibrium were induced rather than the intense ones elicited by flash-photolysis).

After his retirement in 1965, Norrish remained a senior fellow at his old college, Emmanuel. Having lived in Cambridge most of his life, Norrish felt an abiding affection for all things dealing with the university. Famous for his hospitality, Norrish held at-homes with an eclectic blend of cultural personalities in attendance. He died on June 7, 1978, in Cambridge.