Accuracy of Partial Core Corrections Using Fourier Transforms in Pseudopotential–Density Functional Theory

Journal Article · Tue Nov 06 00:00:00 EST 2018 · Journal of Chemical Theory and Computation

DOI:https://doi.org/10.1021/acs.jctc.8b00820· OSTI ID:1543631

Gao, Weiwei ^[1]; Chelikowsky, James R. ^[1]

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1. Univ. of Texas, Austin, TX (United States). Inst. for Computational Engineering and Sciences, Center for Computational Materials

Partial core corrections can be important in obtaining an accurate description of nonlinear exchange-correlation functionals and improving the transferability of pseudopotentials. We show that a widely used procedure, which calculates partial core charge density, $$ρ^{partial}_{core}$$, in Fourier space and then converts it to real space with fast Fourier transforms, can lead to sizable numerical errors of exchange-correlation potentials in the vacuum region. Such errors occur in modeling low-dimensional materials or surfaces with supercells. The loss of accuracy originates from the slow-decaying feature of core charge density in reciprocal space. Numerical errors on the order of 1 eV in the Kohn–Sham energies of unoccupied states can occur in pseudopotential–density functional calculations. The direct calculation of the partial core charge in real space can avoid the numerical errors caused by Fourier transforms.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Univ. of California, Oakland, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1543631
• Journal Information: Journal of Chemical Theory and Computation, Journal Name: Journal of Chemical Theory and Computation Journal Issue: 12 Vol. 14; ISSN 1549-9618
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

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