An approximate discretized real time path integral simulation method for nearly classical systems

A new approximate technique for real time discretized path integral simulations is introduced. The technique transforms the oscillatory integrands into nonoscillatory functions for accurate Metropolis Monte Carlo evaluation. The method is applied to a system containing a Br2 diatomic in two Ar atoms. The vibrational transition probability of finding the diatomic in its ground vibrational state is calculated at time t. The diatomic is initially in its first vibrational state. Computations are carried out for two different times and the results are compared to the previously published results of full discretized path integral calculation. The convergence of the technique is tested as a function of the number of points in the discretized solvent path.