A BORN-GREEN-YVON EQUATION FOR FLEXIBLE CHAIN MOLECULE FLUIDS .1. GENERAL FORMALISM AND NUMERICAL RESULTS FOR SHORT HARD-SPHERE CHAINS

The Born-Green-Yvon approach is used to construct an integral equation for the site-site distribution functions describing the microscopic equilibrium structure of a fluid of flexible chain molecules. The multisite distribution functions appearing in this formally exact equation are related to the site-site functions via a set of site-site superposition approximations. Intramolecular distribution functions are approximated using exact results for an isolated chain molecule. Numerical results are presented for fluids of tangent hard-sphere 3-mers and 4-mers. These results, which include the site-site distribution functions over a range of densities, second virial coefficients, and the virial pressure equations of state, compare well with Monte Carlo data. In particular, the contact value of the average site-site distribution function is given quite accurately. © 1995 American Institute of Physics.