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  • 1607.01544v2

    Rights statement: © 2016 American Physical Society

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Trail-Needs pseudopotentials in quantum Monte Carlo calculations with plane-wave/blip basis sets

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Article number165170
<mark>Journal publication date</mark>15/10/2016
<mark>Journal</mark>Physical review B
Issue number16
Volume94
Number of pages9
Publication StatusPublished
<mark>Original language</mark>English

Abstract

We report a systematic analysis of the performance of a widely used set of Dirac-Fock pseudopotentials for quantum Monte Carlo (QMC) calculations. We study each atom in the periodic table from hydrogen (Z = 1) to mercury (Z = 80), with the exception of the 4f elements (57 ≤ Z ≤ 70).
We demonstrate that ghost states are a potentially serious problem when plane-wave basis sets are used in density functional theory (DFT) orbital-generation calculations, but that this problem can be almost entirely eliminated by choosing the s channel to be local in the DFT calculation; the
d channel can then be chosen to be local in subsequent QMC calculations, which generally leads
to more accurate results. We investigate the achievable energy variance per electron with different
levels of trial wave function and we determine appropriate plane-wave cutoff energies for DFT calculations for each pseudopotential. We demonstrate that the so-called “T-move” scheme in diffusion Monte Carlo is essential for many elements. We investigate the optimal choice of spherical integration rule for pseudopotential projectors in QMC calculations. The information reported here will prove crucial in the planning and execution of QMC projects involving beyond-first-row elements.

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© 2016 American Physical Society