Ronald Norrish

Flash photolysis, developed by Ronald Norrish and George Porter at the University of Cambridge, is a technique that uses brief, intense flashes of light to initiate chemical reactions and observe their short-lived intermediates. The method revolutionized the study of fast chemical reactions by making transient species directly observable for the first time.

Norrish shared the 1967 Nobel Prize in Chemistry with George Porter and Manfred Eigen for their development of techniques to study extremely fast chemical reactions. Porter had been Norrish's student at Cambridge, and their collaboration on flash photolysis was central to the award.

The Norrish Type I and Type II reactions describe two distinct photochemical fragmentation pathways of carbonyl compounds that Norrish identified using flash photolysis. Type I involves cleavage of the bond between the carbonyl carbon and an alpha carbon to produce radicals, while Type II involves intramolecular hydrogen abstraction through an excited triplet state.

Ronald Norrish spent his career at the University of Cambridge, where he headed the Department of Physical Chemistry. His Cambridge laboratory was where flash photolysis was developed and refined into a widely adopted technique for studying reaction kinetics.