Semiclassical Monte Carlo path integration for the time-domain treatment of barrier tunneling: bifurcations into real and imaginary trajectories

Semiclassical Monte Carlo path integration including real and imaginary trajectories has been attempted for a time-domain treatment of barrier tunneling. In the present scheme, each classical path is bifurcated into real and imaginary trajectories at a given point under the connecting conditions that provide accurate momentum distributions as t → + ∞. The numerical test for the H + H2 reaction modelled by the Eckart potential showed a significant improvement in reproducing the non-classical effects.