Additive atomic approximation for relativistic effects: a two-component Hamiltonian for molecular electronic structure calculations

Dimitri N. Laikov

doi:10.1063/1.5082231

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arXiv · 1811.08123

Additive atomic approximation for relativistic effects: a two-component Hamiltonian for molecular electronic structure calculations

Dimitri N. Laikov

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Abstract

An approximate relativistic two-component Hamiltonian for use in molecular electronic structure calculations is derived in the form of a sum of fixed atom-centered kinetic and spin-orbit operators added to the non-relativistic Hamiltonian. Starting from the well-known zeroth-order regular approximation, further steps are taken to get rid of its nonlinearity in the potential, ending up with a simple formulation with easily computable integrals that can seamlessly work with any traditional electronic structure method. Molecular tests show a good accuracy of this approximation.

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Dimitri N. Laikov. 2018-11-20. Additive atomic approximation for relativistic effects: a two-component Hamiltonian for molecular electronic structure calculations. https://doi.org/10.1063/1.5082231

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