The Infra-Red Absorption by Hydrogen Selenide, Deuterium Selenide and Deutero-Hydrogen Selenide

The infra-red spectra of H2Se, D2Se and HDSe have been measured and the positions of the three fundamental frequencies for each molecule have been determined. These are; for H2Se v1 = 2260 cm—1, v2 = 1074 cm—1, v3 = 2350 cm—1; for D2Se, v1 = 1630 cm—1, v2 = 745 cm—1, v3 = 1696 cm—1; for HDSe, v1 = 1691 cm—1, v2 = 905 cm—1 and v3 = 2352 cm—1. Interpretation of the observed data has led to the adoption of an obtuse model where the H–Se–H bond angle is slightly in excess of 90°. The H–Se distances are evaluated to be 1.6A and the H–H distance is equal to 2.3A. The product relations of Redlich are made use of as a verification of a correct assignment of frequencies and for a correct determination of the band centers.