Nonlocal pseudopotentials and diffusion Monte Carlo

Journal Article · Sun Sep 01 00:00:00 EDT 1991 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.460849· OSTI ID:5268066

Mitas, L ^[1]; Shirley, E L ^[2]; Ceperley, D M ^[3]

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1. University of Illinois at Urbana-Champaign, Urbana, Illinois (USA). Department of Physics
2. Illinois Univ., Urbana, IL (USA). Materials Research Lab. Illinois Univ., Urbana, IL (USA). Dept. of Physics
3. Illinois Univ., Urbana, IL (USA). Center for Supercomputing Research and Development University of Illinois at Urbana-Champaign, Urbana, Illinois (USA). Department of Physics

We have applied the technique of evaluating a nonlocal pseudopotential with a trial function to give an approximate, local many-body pseudopotential which was used in a valence-only diffusion Monte Carlo (DMC) calculation. The pair and triple correlation terms in the trial function have been carefully optimized to minimize the effect of the locality approximation. We discuss the accuracy and computational demands of the nonlocal pseudopotential evaluation for the DMC method. Calculations of Si, Sc, and Cu ionic and atomic states and the Si{sub 2} dimer are reported. In most cases {similar to}90% of the correlation energy was recovered at the variational level and excellent estimations of the ground state energies were obtained by the DMC simulations. The small statistical error allowed us to determine the quality of the assumed pseudopotentials by comparison of the DMC results with experimental values.

• DOE Contract Number: FG02-91ER45439
• OSTI ID: 5268066
• Journal Information: Journal of Chemical Physics; (United States), Vol. 95:5; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ATOMS
ELECTRON CORRELATION
COPPER
SCANDIUM
SILICON
DIFFUSION
DIMERS
ELECTRONIC STRUCTURE
GROUND STATES
MANY-BODY PROBLEM
MONTE CARLO METHOD
VALENCE
CORRELATIONS
ELEMENTS
ENERGY LEVELS
METALS
SEMIMETALS
TRANSITION ELEMENTS
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory