Raman spectroscopic studies of S 16 O 2 and S 18 O 2 in the gas phase: Hot band assignment

Raman spectra have been obtained for the fundamental modes of S 16 O 2 and S 18 O 2 in the gaseous phase: S 16 O 2 , ν 1 =1151.3, ν 2 =518.2, ν 3 =1361.5; 18 O 2 , ν 1 =1100.8, ν 3 =1318.0 cm −1 . Band shapes for the isotopically different molecules are essentially identical and conform to expectations for a nearly prolate symmetric top molecule. Accurate isotopic shifts for a number of naturally abundant isotopically different molecules are reported. A weak peak shifted −3.1 cm −1 from the ν 1 peaks of S 16 O 2 and S 18 O 2 has been assigned to the hot band transition 010→110. This assignment has been confirmed by temperature variation studies of S 16 O 2 in CCl 4 liquid.