Étude des bandes infrarouges en résonance 2ν2, ν2 + ν5, , , 2ν3 + ν5 et 4ν3 du chlorure de méthyle

Abstract

The spectrum of methyl chloride has been analyzed between 2650 and 2950 cm−1 from Fourier transform recordings obtained with a very high resolution. More than 3000 lines of CH335Cl and more than 1500 lines of CH337Cl, most of them belonging to ν2 + ν5 and [Formula: see text], have been assigned: the 2ν2, [Formula: see text], 4ν3 and 2ν3 + ν5 bands are very weak and only appear when there are level crossings. The main interaction is the Coriolis resonance between the ν2 and ν5 modes, which links the rovibrational levels six by six. The Fermi resonance between [Formula: see text] and ν1, whose existence has just been shown, does not seem to have important consequences. Numerous other resonances, particularly making the 4ν3 and 2ν3 + ν5 bands visible, must be added to the basic coupling model; they make the general interaction scheme extremely complex. A least squares calculation, according to a simplified model, has given a standard deviation of 0.029 cm−1 over 784 lines of CH337Cl, from which crossings and locally perturbed subbands were excluded.