Infra-Red and Raman Spectra of Polyatomic Molecules. IV. Allene

Abstract

The infra-red absorption spectrum and the Raman spectrum of allene were examined. In the infra-red nine bands were observed at 4200, 2960, 2420, 1980, 1700, 1389, 1165, 1031 and 852 cm—1 and in the Raman effect there were ten individual shifts of 3062, 2992, 2858, 1956, 1684, 1430, 1069, 838, 705 and 353 cm—1. With the aid of heat capacity data it was possible to assign values to the frequencies of all the eleven fundamental modes of vibration of allene. The assignment accounted for all the features of the Raman and infra-red spectra. Calculations were made of the free energy, the entropy and the heat capacity and expressions for the first two, as functions of temperature, derived.