MOLECULAR-DYNAMICS SIMULATION STUDY OF DENSITY EFFECTS ON VIBRATIONALDEPHASING IN DIATOMIC MOLECULAR LIQUID N2

Molecular dynamics simulation was carried out to study density effects on vibrational dephasing. Because of difficulty due to large time sca le difference between vibrational motion and vibrational relaxation, w e adopt adiabatic approximation in which the vibrational motion is ass umed to be much faster than translational and rotational motion. As a result, we are able to study vibrational dephasing by simulating motio n of rigid molecules. It is shown that the dephasing time is decreased as density increases and the contribution to this result is mainly du e to the mean-squared frequency fluctuation.