Nonstatistical energy flow in the first N–H stretch overtone region of methylamine

Methylamine (CH3NH2) molecules, excited to vibrational states lying in the energy window of the first N–H stretch overtone, were studied by room temperature photoacoustic spectroscopy and jet-cooled action spectroscopy. Benefiting from both types of spectra and specifically from the narrowed action spectrum, a multiband structure was revealed. Simulation of the spectral contours allowed retrieving the band origins, band types and transition linewidths. The linewidths indicate that the energy redistribution occurs nonstatistically and that the 2ν10 state (antisymmetric N–H stretch) is relatively longer lived.