Benchmark quantum Monte Carlo calculations
- 22 July 2002
- journal article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 117 (4), 1434-1440
- https://doi.org/10.1063/1.1487829
Abstract
Fixed node diffusion Monte Carlo (FN-DMC) atomization energies are calculated for a benchmark set of 55 molecules. Using single determinant trial wave functions, comparison with experiment yields an average absolute deviation of 2.9 kcal/mol, placing this simplest form of FN-DMC roughly at the same level of accuracy as the CCSD(T)/aug-cc-pVQZ method. However, unlike perturbative wave function expansion approaches, FN-DMC is applicable to systems containing thousands of valence electrons. For the molecule, a number of possible sources of error are explored in detail. Results show that the main error is due to the fixed-node approximation and that this can be improved significantly with multireference trial wave functions.
Keywords
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