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

Drummond, Neil David and Trail, J. R. and Needs, Richard (2016) Trail-Needs pseudopotentials in quantum Monte Carlo calculations with plane-wave/blip basis sets. Physical review B, 94 (16). ISSN 1098-0121

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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.

Item Type: Journal Article
Journal or Publication Title: Physical review B
Additional Information: © 2016 American Physical Society
Departments: Faculty of Science and Technology > Physics
ID Code: 82487
Deposited By: ep_importer_pure
Deposited On: 27 Oct 2016 15:36
Refereed?: Yes
Published?: Published
Last Modified: 21 Oct 2019 00:52
URI: https://eprints.lancs.ac.uk/id/eprint/82487

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