Raman and infrared spectra of the ν1 band of oxirane

Abstract

Fourier transform spectra of oxirane [ethylene oxide (c-C2H4O)] have been recorded in the 3.17 μm–3.50 μm region with a resolution of 0.005 cm− 1. In addition, a Raman spectrum covering the same spectral region was recorded at a resolution of 0.44 cm− 1. Using the Raman spectrum, it was possible to determine the band centre of the ν1 band to within 0.5 cm− 1. This determination was essential to assign the infrared region transitions of the B-type ν1 band since this weak band is masked by the much stronger A-type bands ν2 + ν10 and ν9 and ν13 C-type band. Using a Watson-type Hamiltonian for an asymmetric-top molecule, it was possible to reproduce the observed energy levels to within 2 × 10− 3 cm− 1 and the Raman spectrum could be satisfactorily modelled. The band centre was determined to be ν0 (ν1) = 3018.3454(10) cm− 1 (1 σ uncertainty).