Fast calculation of thermodynamic and structural parameters of solutions using the 3DRISM model and the multi-grid method

TL;DR

This paper introduces a multi-grid based algorithm for solving 3DRISM equations, significantly reducing computational time while maintaining high accuracy in solvation free energy calculations for various solutions.

Contribution

The paper presents a novel multi-grid algorithm for 3DRISM that decreases computational costs and improves efficiency compared to traditional methods.

Findings

Calculations on a 0.05 Å grid with an 8 Å buffer achieve less than 0.3 kcal/mol error.

The new algorithm is over 12 times faster than the standard Picard method.

High accuracy in solvation free energy predictions comparable to experimental data.

Abstract

In the paper a new method to solve the tree-dimensional reference interaction site model (3DRISM) integral equations is proposed. The algorithm uses the multi-grid technique which allows to decrease the computational expanses. 3DRISM calculations for aqueous solutions of four compounds (argon, water, methane, methanol) on the different grids are performed in order to determine a dependence of the computational error on the parameters of the grid. It is shown that calculations on the grid with the step 0.05\Angstr and buffer 8\Angstr give the error of solvation free energy calculations less than 0.3 kcal/mol which is comparable to the accuracy of the experimental measurements. The performance of the algorithm is tested. It is shown that the proposed algorithm is in average more than 12 times faster than the standard Picard direct iteration method.