High-resolution stimulated Raman spectroscopy and analysis of the ν1/ν5 (C-H) stretching dyad of C2H 4

Abstract

The high-resolution stimulated Raman spectra of the ν1/ ν5 C-H stretching bands of C2H4 have been recorded and analyzed by means of the tensorial formalism developed in Dijon for X2Y4 asymmetric-top molecules. A total of 689 lines (428 for ν5 and 261 for ν1) were assigned and fitted as a dyad including Coriolis coupling constants. We obtained a global root mean square deviation of 4.39 × 10- 3 cm- 1 (4.61 × 10- 3 cm- 1 for ν1, 4.25 × 10 - 3 cm- 1 for ν5). The nearby 2ν2 band, extrapolated from ν2, was included in the analysis. However, no interaction parameter involving it could be fitted. The analysis is quite satisfactory, although some parts of ν5 are not very well reproduced, probably indicating some yet unidentified resonances. This region is indeed quite dense, with many interacting dark states that cannot be included at present. Copyright © 2012 John Wiley & Sons, Ltd.