THE 2-NU(8)-BAND OF CH3CN

The overtone band 2ν08 of CH3CN around 720 cm-1 has been measured on a Bruker Fourier transform spectrometer at a resolution of 0.003 cm-1. Only the parallel band was observed, but due to the l(2, 2) resonance, ΔK = -2 lines leading to the v8 = 2, l8 = -2 levels with K = 1-3 could be seen. More information for the l8 = ±2 component of the vibrational state v8 = 2 was evaluated from the hot band 2ν±28 - ν±18. Altogether more than 1000 lines were assigned. In the fit pure rotational lines from literature were also combined. Among the results the anomalous A0 - A′ values 4.6722(13) × 10-3 cm-1 for the 2ν08 band and 7.0324(32) × 10-3 cm-1 for the 2ν±28 band are striking. © 1993 Academic Press, Inc.