Relativistic semistochastic heat-bath configuration interaction

TL;DR

This paper extends the semistochastic heat-bath configuration interaction method to relativistic Hamiltonians, enabling accurate treatment of electron correlation and relativistic effects in complex systems like gold and neptunium compounds.

Contribution

The work introduces a relativistic extension of SHCI that can handle two- and four-component Hamiltonians, broadening its applicability to relativistic quantum chemistry problems.

Findings

Calculated VDE of AuH_2^- with high accuracy.

Determined ZFS of NpO2 2+ considering relativistic effects.

Demonstrated SHCI's capability for relativistic electron correlation calculations.

Abstract

In this work we present the extension of semistochastic heat-bath configuration interaction (SHCI) to work with any two-component and four-component Hamiltonian. Vertical detachment energy (VDE) of AuH_2^- and zero-field splitting (ZFS) of NpO2 2+ are calculated by correlating more than 100 spinors in both cases. This work demonstrates the capability of SHCI to treat problems where both relativistic effect and electron correlation are important.