JUNE, 1951
KLAUS CLUSIUS RALPH E. OESPER University of Cincinnati,.Cincinnati, Ohio
KLAUSCLUSIUS,eminent physical chemist, was born a t Breslau on March 19, 1903. He received the Dr. Ing. degree from the Breslau Technische Hochschule in 1928. A Rockefeller stipend allowed him to spend one year a t Oxford under C. N. Hinshelwood and several months a t Leiden where he worked under W. A. Keesom in the Kammerlingh-Onnes Laboratory. His teaching career began a t Gottingeu, where he habilitated in physical chemistry in 1931. He was called to Wiirzburg as associate professor in 1934 and after two years was appointed department head a t Munich. He entered his present position, Director of the PhysikalischChemisches Institut a t the University of Zurich, in 1947. Professor Clusius has successfully devoted himself t o a variety of research topics. His main fields of interest have been reaction kinetics, low temperature studies, and investigation of isotopes. The work on reaction kinetics began in Hinshelwood's laboratory, with studies of homogeneous gas catalysis. Recently, particular attention has been given to flame reactions. The spreading and form of hydrogen flames a t the lower explosion limit and the accompanying diffusion processes mere explained with the aid of heavy hydrogen and "colored" flames. The radical change in
the structure of carbon suboxide flames by drying is one of his newer discoveries. The low temperature studies have dealt especially with specific heats, heats of transition, heats of fusion, and the entropy of condensed gases. The singular division of the transformation of methane CH4 a t 20' absolute into two transitions in the case of CH8D and CD4 was established. I n other instances, such isotopic effects resulted in considerable shifts of the transition points of "deuterized" gases. The separating tube process was discovered in 1938. It makes possible an enormous increase in the conceutration shift of gaseous and liquid isotopes as compared with the slight effect achieved by thermodiffusion. The process was subsequently developed with the collaboration particularly of G. Dickel and H. Kowalski. By this means, for the first time C13j and C13', KrR4 and KrR6,018,and recently N1j were obtained a t a purity of over 99 per cent. N2% and N20,first separated by Hertz, could now be obtained by the liter. Professor Clusius is a member of the Academies of Munich, Halle, and Bologna. I n 1940 he was awarded the Arrhenius Prize of the University of Leipzig, and in 1943 he was the recipient of the Caunizzaro Prize of the Accademia dei Lincei in Rome.
