A study on the transferability of the sigma enlarging bridge function for an accurate evaluation of solvation free energy: The case of homonuclear Lennard-Jones diatomic solute solvated in a Lennard-Jones monatomic solvent

Tatsuhiko Miyata,Naoya Yabuki

doi:10.1063/1.5087935

Abstract

We study the applicability of sigma enlarging bridge (SEB) function to a homonuclear Lennard-Jones (LJ) diatomic solute molecule solvated in an LJ monatomic solvent, where the SEB was originally proposed for a monatomic solute molecule to improve the accuracy of the solvation free energy (SFE) [T. Miyata, Bull. Chem. Soc. Jpn. 90, 1095 (2017)]. Our interest is focused on the transferability of the SEB parameter, which is a parameter included in the SEB function. We employ the two-dimensional Ornstein-Zernike (OZ) theory. Hypernetted chain (HNC), Kovalenko-Hirata (KH) and Percus-Yevick (PY) closures are considered. The HNC closure with the SEB correction (SEB-HNC) and the counterpart for the KH closure (SEB-KH) are also examined in terms of the SFE. It is found that by comparing with the molecular dynamics simulation, the SFE is overestimated under both HNC and KH closures, whereas it tends to be underestimated under PY closures. These results are similar to those obtained for systems of LJ monatomic solute molecules. Both the SEB-HNC and the SEB-KH closures provide quite an accurate SFE, when the SEB parameter values that were originally evaluated for a monatomic solute molecule are applied to the homonuclear LJ diatomic solute. This indicates that the SEB parameter is transferable. The transferability of the SEB parameter is also confirmed in terms of the angular-dependent one-dimensional distribution function, which is obtained from the two-dimensional distribution function. The validity of the partial molar volume correction is also discussed by examining the dependence of the SFE errors on the solute volume.

Highlights

Molecular modeling1 has become an important point of view in a variety of fields
Even if we narrow down the system of our interest to the liquid state, we can raise the following examples: aqueous solution of protein molecules,2–8 molecular recognition concerning the protein,9–12 solubilization of micelles,13,14 free energy calculation of polymer solution,15,16 and all-atom molecular dynamics (MD) simulation of scitation.org/journal/adv entire poliovirus in water
We have examined the transferability of the sigma enlarging bridge (SEB) function using the 2D-OZ equation for a homonuclear LJ diatomic solute molecule solvated in LJ monatomic solvent

Summary

Introduction

Molecular modeling has become an important point of view in a variety of fields. The fields that need a molecular modeling include physics, chemistry, biology, drug design, medical science, engineering, agricultural science, and so on. An existing general potential (or Hamiltonian) such as AMBER, CHARMM, OPLS, GROMOS21 and so on is frequently used in such a case Almost all of these general potentials adopt the function form of the superposition of the Lennard-Jones (LJ) potential and the coulomb potential: namely, the quality of the molecular modeling depends on the total performance resulting from the combination of LJ and coulomb potentials including the assigned parameter values to describe a variety of materials. Taking these circumstances into consideration, we set the final goal of our study at a precise molecular modeling assuming the combination of the LJ potential and the coulomb potential

Objectives

Results

Conclusion