Time-correlation functions in molecular liquids studied by the mode-coupling theory based on the interaction-site model

Numerical results for longitudinal current spectra, velocity autocorrelatio n functions, and diffusion coefficients of a model diatomic liquid are pres ented using the recently developed theory for dynamics of classical polyato mic fluids. The theory is based on the interaction-site model for molecular liquids, the projection-operator formalism, and mode-coupling theory. The effect of the inclusion of a slow contribution in memory kernels, represent ed by the mode-coupling expression, on the aforementioned dynamical quantit ies is discussed. A molecular dynamics simulation of the same system is als o performed to test the accuracy of our theory, and the theoretical results are found to be in fair agreement with those obtained from the simulation. [S1063-651X(98)01412-3].