Large-amplitude torsional motion as a generator of vibrational energy redistribution within polyatomic molecules.

by David S. Perry
Department of Chemistry, The University of Akron

Methanol and nitromethane are used as case studies of intramolecular vibrational redistribution (IVR) in torsional molecules. The former has a moderate 3-fold torsional barrier and the latter is almost a free internal rotor with a very low 6-fold barrier. The approximate adiabatic separation of the torsion from the other small amplitude vibrations is used as a guiding concept in exploring IVR in these systems. The results presented will include (i) the scaling properties of IVR in methanol with coupling order, (ii) new modes of vibration born in methanol at high energy, (iii) torsionally mediated IVR in nitromethane, and (iv) the conformational dependence of IVR in methanol.