Importance of high-angular-momentum channels in pseudopotentials for quantum Monte Carlo

Tipton, W. W. and Drummond, Neil and Hennig, R. G. (2014) Importance of high-angular-momentum channels in pseudopotentials for quantum Monte Carlo. Physical review B, 90 (12). ISSN 1098-0121

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Abstract

Quantum Monte Carlo methods provide in principle a highly accurate treatment of the many-body problem of calculating the ground and excited states of condensed systems. In practice, however, uncontrolled errors, such as those arising from the fixed-node and pseudopotential approximations can be problematic. We show that the accuracy of some quantum Monte Carlo calculations is limited by the properties of currently available pseudopotentials. The use of pseudopotentials involves several approximations, and we will focus on one that is relatively simple to correct during the pseudopotential design phase. It is necessary to include angular-momentum channels in the pseudopotential for excited angular-momentum states and to choose the local channel appropriately to obtain accurate results. Variational and diffusion Monte Carlo calculations for Zn, O, and Si atoms and ions demonstrate these issues. Adding higher-angular-momentum channels into the pseudopotential description reduces such errors without a significant increase in computational cost.

Item Type:
Journal Article
Journal or Publication Title:
Physical review B
Additional Information:
©2014 American Physical Society
ID Code:
76456
Deposited By:
Deposited On:
03 Nov 2015 19:17
Refereed?:
Yes
Published?:
Published
Last Modified:
27 Oct 2020 04:51