The solution of the wertheim association theory for molecular liquids: Application to hydrogen fluoride

摘要

A general numericla metho for solving the Werthim association theory in the case of fully anisotropic polyatiomic rigid molecules is proposed. In order to handle the nonsphericla shapes of the molecules, the Wertheim association theory is combined with the rotational invariant approach of the molecular Ornstein-Zernike(MOZ) method. Therefore, this approach is called the WMOZ mehod. It is carried out in the association hypernetted chain(AHNC)approximation which is the only approximation and which consists of the neglect of the bridge functions. The method of solution is implemented by translating the set operations appearing in the Wertheim association theory into an algebriaic formatlism developed through a one-to-one correspondence between subsets and binary numbers. The Wertheim association theory is explicitly solved for hydogen fluoride using two interaction site models. For these models, site-site distribution functions ,internal excess energies, and dielectric constants obtained by the MOZ and WMOZ method strongly improves the s tyructural description of the H bonding in comparison with the MOZ approximation. The quality of the dielectric and thermodynamic results obtained by the WMOZ approach is discussed in comparison with the simulation values. To our knowledge, this is the first solution of the Wertheim association theory for a liquid of particles of nonspherical shapes