Electronic stress tensor of the hydrogen molecular ion: Comparison between the exact wave function and approximate wave functions using Gaussian basis sets

TL;DR

This paper compares the electronic stress tensor of the hydrogen molecular ion using exact and approximate wave functions, showing that large basis sets like cc-pV6Z closely replicate the exact results.

Contribution

It demonstrates the accuracy of high-level Gaussian basis sets in reproducing the electronic stress tensor features of the hydrogen molecular ion.

Findings

cc-pV6Z basis set closely matches the exact wave function results

Energy density at the Lagrange point is well approximated by cc-pV5Z and cc-pV6Z

Spindle structure is accurately reproduced with cc-pV6Z basis set

Abstract

We investigate the electronic stress tensor of the hydrogen molecular ion for the ground state using the exact wave function and wave functions approximated by gaussian function basis set expansion. The spatial distribution of the largest eigenvalue, corresponding eigenvectors, tension and kinetic energy density are compared. We find that the cc-pV6Z basis set gives the spindle structure very close to the one calculated from the exact wave function. Similarly, energy density at the Lagrange point is very well approximated by the cc-pV5Z or cc-pV6Z basis sets.