HIRSHBERG, YEHUDAH (1905–1962), Israeli physical chemist. Hirshberg, who was born in Poland, went to Palestine in 1923 to join a kibbutz. In 1933 he joined the Daniel Sieff Institute (later part of the Weizmann Institute) at Reḥovot. Hirshberg worked on the photochemistry of glycine, alcohols, aldehydes, the deamination of amino acids, the decomposition of solid compounds of hydrogen at low temperatures, absorption spectroscopy, fluorescence spectra, photoisomerization, and other effects of light. Essentially an experimentalist, Hirshberg discovered the phenomenon of photochromism – the reversible transformation of colorless dianthrones by ultraviolet light into colored forms, and also of spiropyrans by visible light.
Journal of Chemical Education, 40 (1963), 112–3.
[Samuel Aaron Miller]