Fluids of hard-core triatomic molecules. Computer simulations of polyatomic molecules. Part 4.—Monte Carlo simulations of hard-core triatomics

Abstract

Monte Carlo simulations have been carried out for systems of 500 symmetric, linear triatomic molecules composed of fused hard spheres. Orientational ordering in these systems has been examined by calculating two types of distribution functions: (1) angle-dependent pair distribution functions, g(r₁₂ω₁ω₂), expanded in spherical harmonics; and (2) site–site distribution functions, g_αβ(r_αβ), which describe the distribution of atom centres. Pressures calculated from a virial-like equation have been compared with several theoretical estimates based on modifications of the Carnahan–Starling equation. Structure factors, H_d(k), have been calculated by Fourier transforming the g_αβ(r_αβ), and the results compared with recent X-ray and neutron scattering data for CS₂. The calculated g_αβ(r_αβ) have been compared with values predicted by the reference interaction site model (RISM) equation.