Global analysis of 12CH335Cl and 12CH337Cl: simultaneous fit of the lower five polyads (0-2600 cm−1)

The global analysis of the infrared spectrum of chloromethane involving the ground state and the 13 vibrational states lying up to 2600 cm−1 is reported. This work incorporates and extends to the fifth polyad, the preliminary study of the lower four polyads published by [J. Mol. Spectrosc. 221 (2003) 199]. More than 20 000 transitions (including numerous hot bands) for each isotopomer 12CH335Cl and 12CH337Cl have been assigned and fitted with a standard deviation of about 3 × 10−4 cm−1 close to the experimental precision. A common set of 288 (resp. 303) effective parameters was determined for each isotopomer. Our global model allowed us to reproduce simultaneously and accurately the resonances already encountered in Polyad 3 and the new ones involved in Polyad 5.