Structures of fused-dimer fluids: A new closure based on the potential distribution theorems

摘要

We carry out Monte Carlo (MC) simulation as well as solution of the Chandler-Silbey-Ladanyi (CSL) equations with self-consistent closures for symmetric hard dumbbells with bond lengths L = 0.1, 0.4, 0.6, 0.8, and 1.0. The consistency conditions include the zero-separation theorems, the pressure consistency (P-v = P-c), and the overlap conditions. Conventional closures, such as the Percus-Yevick closure, give the wrong sign (negative values) for the unbonded bridge function B-00(r) for small bond lengths L < 0.8; the MC-determined behavior of B-00(r) being >0. This explains the failure of the common liquid state closures for chain molecules. The CSL is solved with a set of new closures. The new closure forms are flexible, and are required to satisfy the consistencies imposed. The results are at the same time consistent and highly accurate. (C) 2001 American Institute of Physics. [References: 34]