Correlation Function Method for the Transport Coefficients of Dense Gases. II. First Density Correction to the Shear Viscosity for Systems with Attractive Forces

Extending the technique presented in our earlier work, the correlation-function expression for the shear viscosity is evaluated up to the first-density correction for a classical system of particles interacting with pair and three-body forces of short range which may have attractive parts and may allow for bound states. The results contain new terms as a result of the existence of bound states, in addition to those obtained for the first-density correction to the shear viscosity for the case of purely repulsive forces. In particular, ${\eta }_{\mathrm{KU}}$, ${\eta }_{\mathrm{UK}}$, and ${\eta }_{\mathrm{UU}}$ involve genuine three-body dynamics and give rise to finite contributions to the first-density correction. Diagrams are provided which help to visualize the various processes contributing to the shear viscosity. Finally, higher order density corrections and unstable clusters are briefly discussed.