Collective motion and depolarized light scattering for diatomic fluids

The collective motion of liquid nitrogen is studied by computer simulation. Propagating density waves are found to exist for values of k=2πλ=0.2 ^-1. The orientational motion does not affect the dynamical structure factor for such a small k. The orientational correlation function Σi,j^〈P₂(→uᵢ(0)·→uⱼ(t))〉, which can be related to the depolarized light scattering, is calculated. Comparison with the self term ($i=j$) shows that orientational correlations of neighboring molecules are small.