HIGHLY VIBRATIONALLY EXCITED NON RIGID MOLECULES - OVERTONE SPECTROSCOPY AND INTRAMOLECULAR DYNAMICS OF GASEOUS NITROMETHANE

The CH stretching overtone spectra of gaseous nitromethane NO2CH3 (Del ta nu = 4 to 6) and of its monohydrogenated derivative NO2CHD2 (Delta nu = 2 to 6) have been recorded and analysed with a theoretical treatm ent which takes into account the coupling of the CH stretch with the l ow hindered internal rotation of the methyl group and with isoenergeti c combination states by Fermi resonance. The calculated spectra reprod uce well the experimental ones.