On the role of nonergodicity and slow IVR in unimolecular reaction rate theory—A review and a view

Wave Packet Study of Ultrafast Relaxation in Ice Ih and Liquid Water. Resonant Intermolecular Vibrational Energy Transfer

“…This type of dynamics is often assumed in the study of phonons in solids and vibrational dynamics of molecules, for example, in the Slater theory of reaction rates. 19 Also, harmonic dynamics have been applied to describe processes occurring on short time scales in liquids, thereby providing an analytic shorttime formalism referred to as instantaneous normal mode theory. 20 We are well aware that anharmonic couplings are present and likely to affect the intermolecular motions strongly.…”

Semiclassical Analysis of Multidimensional Barrier Tunneling

“…A central motivation for the study of vibrational energy flow in molecules has long been its influence on spectroscopy [1][2][3][4][5][6][7][8][9][10][11], chemical reaction kinetics in gas and condensed phases [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30], and the desire to control chemical reactions with lasers [31][32][33][34][35][36][37]. In large molecules, quantum mechanical effects can both enhance as well as impose severe limitations on energy flow.…”

Influence of vibrational energy flow on isomerization of flexible molecules: Incorporating non-Rice-Ramsperger-Kassel-Marcus kinetics in the simulation of dipeptide isomerization

“…At such energies vibrational redistribution in molecules is often limited or slow. [4][5][6][7][8][9][10][11][12] To locate the IVR threshold, beyond which vibrational energy flows freely over the energy shell, we turn to LRMT, 17,18 which has been developed to describe quantum mechanical energy flow and localization in many nonlinear oscillator systems, [17][18][19] such as the vibrations of a modest-sized molecule. Local random matrix theory reveals that the IVR threshold does not directly depend on the total density of states of the molecule, but on a local density of resonantly coupled states.…”

“…2,3 A great deal of evidence, however, indicates that the rate of conformational isomerization of modest-sized molecules deviates from RRKM predictions due to insufficiently rapid or incomplete energy flow. [4][5][6][7][8][9][10][11][12] The evolution of the structures of a flexible molecule may thus be influenced by the non-RRKM kinetics of transitions between local minima on the PES. In this article, we study the isomerization dynamics of the low-energy conformers of a dipeptide, N-acetyl tryptophan methyl amide ͑NATMA͒, by incorporating a calculation of the isomerization kinetics in which vibrational energy flow is explicitly accounted for into a master-equation calculation of the population dynamics.…”