Simple non-empirical procedure for spin-component-scaled MP2 methods applied to the calculation of dissociation energy curve of noncovalently-interacting systems

TL;DR

This paper introduces a straightforward, non-empirical method to optimize spin-component-scaled MP2 calculations for accurately modeling the dissociation curves of noncovalent systems, closely matching CCSD(T) results.

Contribution

The paper proposes a simple, non-empirical approach to determine optimal scaling coefficients for spin-component-scaled MP2, improving accuracy in noncovalent interaction energy calculations.

Findings

Method accurately reproduces CCSD(T) energies across dissociation curves.

Outperforms conventional MP2, CCSD, and SCS-MP2 methods.

Successfully applied to the challenging Beryllium dimer case.

Abstract

We present a simple and non-empirical method to determine optimal scaling coefficients, within the (spin-component)-scaled MP2 approach, for calculating intermolecular potential energies of noncovalently-interacting systems. The method is based on an observed proportionality between (spin-component) MP2 and CCSD(T) energies for a wide range of intermolecular distances and allows to compute with high accuracy a large portion of the dissociation curve at the cost of a single CCSD(T) calculation. The accuracy of the present procedure is assessed for a series of noncovalently-interacting test systems: the obtained results reproduce CCSD(T) quality in all cases and definitely outperform conventional MP2, CCSD and SCS-MP2 results. The difficult case of the Beryllium dimer is also considered.