Ronald George Wreyford Norrish
Norrish, Ronald George Wreyford (1897-1978), a British chemist, shared the 1967 Nobel Prize in chemistry for helping develop the technique of flash photolysis to measure rapid chemical reactions. In flash photolysis, a gas is exposed to a powerful burst of light that causes it to undergo photochemical reactions. A second flash allows scientists to detect and record those reactions, even those that last a mere fraction of a second. He shared the prize with his former student George Porter and Manfred Eigen of Germany.
The son of a pharmacist, Norrish was a student at Perse Grammar School in Cambridge. He spent much of World War I (1914–1918) as a prisoner of war in Germany. After completing a bachelor's degree in chemistry (1921), and a doctorate in chemistry (1924), at Emmanuel College, Cambridge, he joined the university faculty.
In the 1920's, he studied the photochemistry of potassium permanganate solution, nitrogen dioxide, and various aldehydes and ketones. Until his research was interrupted by World War II (1939–1945), he investigated the correlation between photodecomposition and spectral character, phosphorescence, and other physical phenomena. During the war, the department of chemistry at Cambridge, which Norrish chaired from 1937 until his retirement in 1965, developed incendiary devices and studied ways to suppress the flash from guns.
After the war, Norrish began observing shortlived products of chemical reactions. Starting in 1949, with his student George Porter, Norrish developed flash photolysis. By the end of their 16-year partnership, they were able to use the technique to analyze reaction products that lasted only a thousandth of a millionth of a second.
Norrish modified Draper's law, which showed how photochemical changes could be expressed as a ratio of light intensity times the length of the reaction time. Norrish proved that the ratio should be to the square root of the light intensity.