Stochastic trajectory simulation of femtosecond pump-probe spectroscopy

Regarding the transient spectroscopy of I-2 in rare-gas environments, it is shown how to calculate femtosecond pump-probe signals with the help of the stochastic Langevin equation. The method is very fast due to the introduct ion of an additional parameter which describes the energy flow between the system and environment. The stochastic trajectory approach is tested by com parison with full-scale molecular dynamics calculations and good agreement is obtained for the signals. The stochastic trajectory simulation can be ap plied to the interpretation of experimental signals and adjustment of exter nal parameters in theoretical models. (C) 2000 Elsevier Science B.V. All ri ghts reserved.