What is the best semiclassical method for photochemical dynamics of systems with conical intersections?

Abstract

We present a systematic test of four general semiclassical procedures for the theoretical treatment of multistate molecular processes such as electronically nonadiabatic photochemical reactions. The methods are tested by comparing their predictions to accurate quantal results for three two-state model reactions involving conical intersections. The four methods tested are Tully's fewest-switches version of trajectory surface hopping ͑1990͒, the Blais-Truhlar trajectory surface hopping method ͑1983͒, the Ehrenfest scheme ͑1975-1979͒, and the Meyer-Miller method ͑1979͒.We test the ability of the classical path methods to predict both electronic probabilities and product rovibrational distributions. For each of the four basic approaches we test six options for extracting final-state information from the calculated dynamics. We find that, although in most cases there is qualitative agreement between average quantum mechanical and trajectory results, the overall average error is about 50% for Tully's fewest-switches method, the Ehrenfest method, and the Meyer-Miller method, and even higher, about 60%, for the Blais-Truhlar method. These values do not include additional errors in the below-threshold regions, which are especially large for the Meyer-Miller method because of the electronic zero-point energy in the Meyer-Miller classical analog Hamiltonian.

The photodissociation of ozone: A quasi-classical approach to a quantum dynamics problem

“…However these single best trajectory approaches, despite being suitable for some scenarios, cannot satisfy a whole range of physical situations, when branching occurs. Trajectory surface hopping (TSH), used in conjunction with the fewest switches algorithm developed by Tully [3] is the most popular and robust method, having been tested and used extensively, notably by Truhlar and co-workers [4,7,[25][26][27][28][29].…”

Intermolecular torsional motion of a π-aggregated dimer probed by two-dimensional electronic spectroscopy

“…We describe the dynamics of the nuclear coordinates by classical trajectories with a time evolution governed by an Ehrenfest type of equation. 36 Thereby the nuclear motion takes place on an averaged potential U(θ ). The specific form of this potential depends on whether populations of electronic states or coherences between them are considered and will be given later in Eqs.…”

Quantum mechanics with the basis set guided by Ehrenfest trajectories: Theory and application to spin-boson model

“…19 and used, for example, in Ref. 20. This technique averages the result over a set of standard single trajectory Ehrenfest dynamics with initial conditions for the classical trajectories which mimic the wave function at t = 0.…”