Application of the Cauchy integral formula as a tool of analytic continuation for the resummation of divergent perturbation series

Zsuzsanna É Mihálka; Ágnes Szabados; Péter R Surján

doi:10.1063/1.5083191

Application of the Cauchy integral formula as a tool of analytic continuation for the resummation of divergent perturbation series

J Chem Phys. 2019 Jan 21;150(3):031101. doi: 10.1063/1.5083191.

Authors

Zsuzsanna É Mihálka¹, Ágnes Szabados¹, Péter R Surján¹

Affiliation

¹ Laboratory of Theoretical Chemistry, Institute of Chemistry, Faculty of Science, ELTE Eötvös Loránd University, 112, P.O. Box 32, H-1518 Budapest, Hungary.

PMID: 30660152
DOI: 10.1063/1.5083191

Abstract

Previous attempts to the resummation of divergent power series by means of analytic continuation are improved applying the Cauchy integral formula for complex functions. The idea is tested on divergent Møller-Plesset perturbation expansions of the electron correlation energy. In particular, the potential curve of the LiH molecule is computed from single reference MPn results which are divergent for bond distances larger than 3.6 Å. Preliminary results for the Hartree-Fock molecule are also tabulated.