Journal article
Investigation of the full configuration interaction quantum Monte Carlo method using homogeneous electron gas models
Journal of Chemical Physics, Vol.136(24), pp.244101-244101
2012
DOI: 10.1063/1.4720076
PMID: 22755559
Abstract
Using the homogeneous electron gas (HEG) as a model, we investigate the sources of error in the "initiator" adaptation to full configuration interaction quantum Monte Carlo (i-FCIQMC), with a view to accelerating convergence. In particular, we find that the fixed-shift phase, where the walker number is allowed to grow slowly, can be used to effectively assess stochastic and initiator error. Using this approach we provide simple explanations for the internal parameters of an i-FCIQMC simulation. We exploit the consistent basis sets and adjustable correlation strength of the HEG to analyze properties of the algorithm, and present finite basis benchmark energies for N = 14 over a range of densities 0.5 ≤ r(s) ≤ 5.0 a.u. A single-point extrapolation scheme is introduced to produce complete basis energies for 14, 38, and 54 electrons. It is empirically found that, in the weakly correlated regime, the computational cost scales linearly with the plane wave basis set size, which is justifiable on physical grounds. We expect the fixed-shift strategy to reduce the computational cost of many i-FCIQMC calculations of weakly correlated systems. In addition, we provide benchmarks for the electron gas, to be used by other quantum chemical methods in exploring periodic solid state systems.
Details
- Title: Subtitle
- Investigation of the full configuration interaction quantum Monte Carlo method using homogeneous electron gas models
- Creators
- James J Shepherd - University of Iowa, ChemistryGeorge H BoothAli Alavi
- Resource Type
- Journal article
- Publication Details
- Journal of Chemical Physics, Vol.136(24), pp.244101-244101
- DOI
- 10.1063/1.4720076
- PMID
- 22755559
- ISSN
- 0021-9606
- eISSN
- 1089-7690
- Language
- English
- Date published
- 2012
- Academic Unit
- Chemistry
- Record Identifier
- 9983985861302771
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