posted on 2024-01-12, 13:36authored byJoseph E. Lawrence, Jonathan R. Mannouch, Jeremy O. Richardson
It is well-known
that fewest-switches surface hopping (FSSH) fails
to correctly capture the quadratic scaling of rate constants with
diabatic coupling in the weak-coupling limit, as expected from Fermi’s
golden rule and Marcus theory. To address this deficiency, the most
widely used approach is to introduce a “decoherence correction”,
which removes the inconsistency between the wave function coefficients
and the active state. Here we investigate the behavior of a new nonadiabatic
trajectory method, called the mapping approach to surface hopping
(MASH), on systems that exhibit an incoherent rate behavior. Unlike
FSSH, MASH hops between active surfaces deterministically and can
never have an inconsistency between the wave function coefficients
and the active state. We show that MASH not only can describe rates
for intermediate and strong diabatic coupling but also can accurately
reproduce the results of Marcus theory in the golden-rule limit, without
the need for a decoherence correction. MASH is therefore a significant
improvement over FSSH in the simulation of nonadiabatic reactions.