INFRARED BAND-NU-8 AND BAND-2-NU-8 OF CD3CN

The high resolution (linewidth 0.0030 cm-1) spectrum of the lowest fundamental band ν8 of CD3CN around 334 cm-1 has been measured on a Bruker Fourier transform spectrometer. In the analysis of more than 2000 assigned lines from 32 subbands even the parameters ηJJ, ηJK, and ηKK proved to be significant. A simultaneous fit together with pure rotational lines from literature was also performed. The parallel overtone band 2ν80 around 661 cm-1 has been measured (linewidth 0.0025 cm-1) and analyzed, too. In the analysis of about 1000 lines the l-resonance was essential. The perpendicular 2ν8 band was not observed, but using some perturbation allowed lines, hot band 2ν8±2-ν8±1 lines, and literature microwave data, the constants for the l = ±2 component of the vibrational state v8 = 2 were evaluated, too. Among the results the anomalous A″-A′ values, 0.77116(30) × 10-3 cm-1 for the 2ν80 band and 1.3193(28) × 10-3 cm-1 for 2ν8±2, are striking. © 1991.