Tight distance-dependent estimators for screening two-center and three-center short-range Coulomb integrals over Gaussian basis functions

TL;DR

This paper introduces new distance-dependent estimators for short-range Coulomb integrals over Gaussian functions, offering tighter bounds and enabling linear-scaling calculations in periodic systems.

Contribution

The authors derive and validate tighter distance-dependent estimators for short-range Coulomb integrals, improving efficiency in solid-state electronic structure calculations.

Findings

Estimators are significantly tighter than Schwarz-based bounds.

Estimators enable linear-scaling computation of periodic three-center integrals.

Validated across diverse periodic systems with various range-separation parameters.

Abstract

We derive distance-dependent estimators for two-center and three-center electron repulsion integrals over a short-range Coulomb potential, $\textrm{erfc}(\omega r_{12})/r_{12}$. These estimators are much tighter than one based on the Schwarz inequality and can be viewed as a complement to the distance-dependent estimators for four-center short-range Coulomb integrals and for two-center and three-center full Coulomb integrals previously reported. Because the short-range Coulomb potential is commonly used in solid-state calculations, including those with the HSE functional and with our recently introduced range-separated periodic Gaussian density fitting, we test our estimators on a diverse set of periodic systems using a wide range of the range-separation parameter $\omega$. These tests demonstrate the robust tightness of our estimators, which are then used with integral screening to calculate periodic three-center short-range Coulomb integrals with linear scaling in system size.