Thermodynamically self-consistent integral-equation theory for pair-correlation functions of a molecular fluid

Abstract

We propose a ''mixed'' integral equation for the pair correlation function of molecular fluids which interpolates between the hypernetted-chain and Percus-Yevick approximations. Thermodynamic consistency between the virial and compressibility equation of state is achieved by varying a single parameter in a suitably chosen mixing function. The integral equation proposed here generalizes the suggestion by Rogers and Young ͓Phys. Rev. A 30, 999 ͑1984͔͒ to an angle-dependent pair potential. When compared to available computer simulation data, the equation is found to yield excellent results for both the thermodynamic properties and the pair-correlation functions. ͓S1063-651X͑96͒02507-X͔ PACS number͑s͒: 61.20.Gy, 61.25.Em

The direct correlation functions of hard Gaussian overlap and hard ellipsoidal fluids

“…They used the PY closure relation and found the spherical harmonic expansion coefficients of the HE DCFs. The results were in agreement with those obtained from computer simulation [17,25]. Rickayzen and coworkers [26,27] introduced the two and three parameters which are based on an ansatz for the HE DCF.…”

“…11 and 12 the obtained compressibility factors, using our DCF, are compared with the other results [25,37] for k ¼ 2 and 3, respectively. In the following we use the closest approach of expression (16) to calculate the isotropic virial coefficientsB 2 andB 3 usinḡ…”

“…We used Eq. (23) to obtain results [25]. The coefficientĈ 0 00 is related to the isothermal compressibility of the liquid,…”

“…To check the results, we compare the coefficients of the PCF with the others. From Y expansion of PCF, gðr 12 ;ŵ 1 ;ŵ 2 Þ, the harmonic coefficients, g l 1 l 2 m ðr 12 Þ, in BF frame, are written as [25].…”

“…k ¼ 3:0. The solid and dotted curves are ours and thermodynamically consistent (TC)[25] results, respectively.…”