Collective motion and depolarized light scattering for diatomic fluids

Abstract

The collective motion of liquid nitrogen is studied by computer simulation. Propagating density waves are found to exist for values of $k=\frac{2\pi }{\lambda }=0.2\mathrm{}$ ${\mathrm{\AA }}^{-1\mathrm{}}$. The orientational motion does not affect the dynamical structure factor for such a small $k$. The orientational correlation function $\Sigma {i,j}^{}〈P_2\left({\overrightarrow{\mathrm{u}}}_i\mathrm{}\right(0\left)\mathrm{}·{\overrightarrow{\mathrm{u}}}_j\mathrm{}\right(t\left)\right)〉$, 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.