THE ROTATIONAL RAMAN SPECTRUM OF ETHYLENE

Abstract

The rotational Raman spectrum of ethylene excited by Hg4358 was photographed with a reciprocal linear dispersion of 10.5 cm.−1 per mm. In addition to S and R branches which, in the symmetric top approximation, can be used to determine B[o] + C[o], the spectrum shows a series of lines which must be interpreted in terms of the asymmetric top model. This series is shown to be due to the transitions, ΔJ = 2, between the two lowest τ levels of each rotational state, and is used to determine C[o]. The rotational constants obtained from the analysis are A[o] = 4.66 ± 0.20, B[o] = 1.0085 ± 0.006, C[o] = 0.8289 ± 0.003 cm−1.