Determination of vibrational parameters of methanol from matrix-isolation infrared spectroscopy and ab initio calculations. Part 1 - Spectral analysis in the domain 11 000-200 cm−1

Infrared spectra of three isotopic species of methanol (12CH316OH, 13CH316OH, 12CH318OH) trapped in neon and nitrogen matrices have been recorded between 11 000 and 200 cm−1. Their analysis is based on the isotopic effects which slightly modify the frequencies without significantly changing the nature of vibrations nor the band intensities. From the assignment of most of the two quanta transitions 45 out of the 78 anharmonicity coefficients have been deduced. The value of some of them has been confirmed by the identification of three quanta transitions mainly involving the OH stretching mode. The problem of vibrational resonances between methyl bending and stretching modes has been tackled by performing complementary experiments: use of other isotopic species (CH3OD, CH2DOH) and acquisition of Raman spectra in the gas phase.