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arXiv · 2111.09271

Perturbation-Adapted Perturbation Theory

Peter J. Knowles
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Abstract

A new general approach is introduced for definining an optimum zero-order Hamiltonian for Rayleigh-Schr\"odinger perturbation theory. Instead of taking the operator directly from a model problem, it is constructed to be a best fit to the exact Hamiltonian within any desired functional form. When applied to many-body perturbation theory for electrons, strongly improved convergence is observed in cases where the conventional Fock hamiltonian leads to divergence or slow convergence.

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Peter J. Knowles. 2021-11-17. Perturbation-Adapted Perturbation Theory. https://doi.org/10.1063/5.0079853

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