Choosing a density functional for static molecular polarizabilities

TL;DR

This study evaluates various density functionals against high-level coupled-cluster reference data for 145 organic molecules to recommend optimal functionals for calculating static molecular polarizabilities.

Contribution

It provides the first comprehensive benchmark of 34 density functionals for static polarizability calculations on small organic molecules.

Findings

Range-separated functionals perform best overall.

Hybrid functionals generally outperform local functionals.

Specific recommendations for functional choice are provided based on molecule size.

Abstract

Coupled-cluster calculations of static electronic dipole polarizabilities for 145 organic molecules are performed to create a reference data set. The molecules are composed from carbon, hydrogen, nitrogen, oxygen, fluorine, sulfur, chlorine, and bromine atoms. They range in size from triatomics to 14 atoms. The Hartree-Fock and 2nd-order M{\o}ller-Plesset methods and 34 density functionals, including local functionals, global hybrid functionals, and range-separated functionals of the long-range-corrected and screened-exchange varieties, are tested against this data set. On the basis of the test results, detailed recommendations are made for selecting density functionals for polarizability computations on relatively small organic molecules.