Knowledge Bank

The infrared spectrum of methylamine, $CH3NH2$, was recorded in the region of the $\nu 1+\nu 10$ N-H stretching overtone ($6600cm-1$), using a molecular beam laser spectrometer with optothermal detection. This molecule is an interesting benchmark for the study of intramolecular vibrational energy redistribution (IVR) because of its two large amplitude internal motions: $CH3$ rotation and $NH2$ wagging that are coupled togethar. However this also makes assigning the spectrum a challenge due to its extreme congestion. The single photon spectrum yields a density of approximately 1000 lines/$cm-1$. Millimeter wave-infrared double resonance has been used to isolate the contributions from a single ground state. Preliminary inspection of the double resonance spectrum suggests that the IVR rates are faster than those observed for molecules of comparable structure and size. Analysis of the data is in progress, and further results will be presented at the conference.