Semiclassical approximations for the calculation of thermal rate constants for chemical reactions in complex molecular systems

Abstract

Articles you may be interested inSemiclassical instanton approach to calculation of reaction rate constants in multidimensional chemical systems J. Chem. Phys. 134, 114103 (2011); 10.1063/1.3565425 Combining semiclassical time evolution and quantum Boltzmann operator to evaluate reactive flux correlation function for thermal rate constants of complex systems Forward-backward initial value representation for the calculation of thermal rate constants for reactions in complex molecular systems On the semiclassical description of quantum coherence in thermal rate constants J. Chem. Phys. 109, 4190 (1998); 10.1063/1.477025Mixed semiclassical-classical approaches to the dynamics of complex molecular systems Two different semiclassical approaches are presented for extending flux correlation function methodology for computing thermal reaction rate constants, which has been extremely successful for the ''direct'' calculation of rate constants in small molecule (ϳ3 -4 atoms) reactions, to complex molecular systems, i.e., those with many degrees of freedom. First is the popular mixed quantum-classical approach that has been widely used by many persons, and second is an approximate version of the semiclassical initial value representation that has recently undergone a rebirth of interest as a way for including quantum effects in molecular dynamics simulations. Both of these are applied to the widely studied system-bath model, a one-dimensional double well potential linearly coupled to an infinite bath of harmonic oscillators. The former approximation is found to be rather poor while the latter is quite good.

Quantum phase-space function formulation of reactive flux theory

“…It is also important to point out that path integral approach also gives rise to several approximations that have a classical flavour 43,44 .…”

Relation of exact Gaussian basis methods to the dephasing representation: Theory and application to time-resolved electronic spectra

“…11,12 In electronic spectroscopy, the DR and closely related approximations are known as phase averaging, 13 Wigner-averaged classical limit, or linearized semiclassical initial value representation 14,15 a) Electronic mail: jiri.vanicek@epfl.ch (LSC-IVR, 16 in the generalized sense 17 ), and have been used by several authors. 14,15,18,19 Although the original formulation of the DR pertains to a single electronic potential energy surface, a generalization to multiple surfaces exists.…”

Efficient on-the-fly ab initio semiclassical method for computing time-resolved nonadiabatic electronic spectra with surface hopping or Ehrenfest dynamics

“…[11][12][13][14][15][16][17][18][19] The DR, which can be directly obtained by the linearization of the path integral, 20 is also closely related to the semiclassical perturbation approximation of Smith, Hubbard, and Miller 21,22 and to the linearized semiclassical initial value representation. 23 Recently, the application of the DR to BornOppenheimer spectra was developed further by improving the accuracy and efficiency using a semiclassical prefactor, 24,25 cellularization, 19,25 and Gaussian basis expansion. 26 Kocia and Heller have extended the method in order to compute the off-diagonal elements of the evolution operator, allowing its use as a general semiclassical propagator.…”