Molecular dynamics studies of depolarized light scattering from argon at various fluid densities

摘要

Molecular dynamics simulations have been used to calculate the twohyphen;, threehyphen;, and fourhyphen;particle contributions to depolarized Rayleigh scattering from argon at various fluid densities. This decomposition is helpful in understanding how the dynamical processes that cause depolarized light scattering vary with density. The twohyphen;, threehyphen;, and fourhyphen;particle time correlation functions decay very slowly in the dense fluid, their relaxation times being an order of magnitude greater than that associated with depolarized Rayleigh scattering. These longhyphen;time tails and their cancellation are explained by a simple diffusional model. The correlation functions obtained from this theory are in agreement with the results of the computer simulation. The high frequency slope of the dense fluid spectrum was found to be similar to that of the pair contribution, but it cannot be unambiguously concluded from this that the high frequency regime of the dense fluid spectrum is dominated by binaryhyphen;like dynamics.