Infrared diodelaser spectrum of the CH _{3}CN ν_{2} band . Analysis of local resonances with ν_{6}^{±1} + 2 ν_{8}^{±2}, ν_{4} + ν_{7}^{±1} + ν_{8}^{±1}, ν_{4} + ν_{6}^{±1}, ν_{4} + ν_{7}^{±1}, and 2 ν_{7}^{0} + ν_{8}^{±1} states
Abstract
Fiftyone sections of infrared diodelaser spectra of acetonitrile have been measured in the region from 2283.5 to 2235.7 cm ^{1}. About 450 transitions belonging to the ν_{2} band have been assigned for K ≦ 7 and J ≦ 44. Anomalies found in the rotational structure have been proven to be due to five local resonances. Observed transition frequencies have been fitted by a leastsquares method to a model which includes Fermitype resonances (∆ k = 0, ∆ℓ = ± 3 n) with ν_{6}^{±1} + 2 ν_{8}^{±2} and ν_{4} + ν_{7}^{±1} + ν_{8}^{±1} states, x, ytype Coriolis resonances (∆ k = ±1, ∆ℓ = ∓3 n ± 1) with ν_{4} + ν_{6}^{±1} and ν_{4} + ν_{7}^{±1} + ν_{8}^{±1} states, and a centrifugaldistortiontype resonance (∆ k = ±2, ∆ℓ = ∓3 n ± 2) with a 2 ν_{7}^{0} + ν_{8}^{±1} state. The 11 × 11 dimensional energy matrix has been diagonalized in order to obtain the perturbed energy levels. The standard deviation for the fit is 1.075 × 10 ^{3} cm ^{1}. The molecular constants determined are also listed.
 Publication:

Journal of Molecular Spectroscopy
 Pub Date:
 July 1985
 DOI:
 10.1016/00222852(85)901985
 Bibcode:
 1985JMoSp.112..127N