Semiclassical dynamics of open quantum systems: Comparing the finite with the infinite perspective

We extend the applicability of the Semiclassical Hybrid Dynamics (SCHD) [F. Grossmann, J. Chem. Phys. 125 (2006) 014111, C.-M. Goletz, F. Grossmann, J. Chem. Phys. 130 (2009) 244107] to the finite temperature case. Results obtained for the thermalization process of a harmonic as well as an anharmonic oscillator are then compared to those obtained using the Semiclassical Brownian Motion method (SCBM) [W. Koch, F. Grossmann, J. T. Stockburger, J. Ankerhold, Phys. Rev. Lett. 100 (2008) 230402]. Since the SCHD method includes individual reservoir modes explicitly, we are able to tailor their distribution to accurately reflect the environmental influence. The details that need to be taken care of in constructing the finite equivalent of the infinite bath are discussed and the relevance for the thermalization process of different modes is investigated.