Extracting rates of vibrational energy relaxation from centroid molecular dynamics

We investigate the ability of centroid molecular dynamics (CMD) to determine quantum correlation functions pertinent to the bath force correlation function, appearing in the rate expression for vibrational energy relaxation. We consider a one-dimensional model consisting of two or three Helium atoms. As expected, it is found that CMD performs best when the dominant bath coupling is linear in the bath coordinates, but it also performs well in determining the high frequency components of the force correlation functions. It is suggested that CMD should be used instead of classical dynamics when studying vibrational energy relaxation in cases where quantum effects are expected to be significant.