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Time step error in diffusion Monte Carlo simulations: An empirical study

✍ Scribed by Stuart M. Rothstein; Narayan Patil; Jan Vrbik

Publisher: John Wiley and Sons
Year: 1987
Tongue: English
Weight: 584 KB
Volume: 8
Category: Article
ISSN: 0192-8651
DOI: 10.1002/jcc.540080418

No coin nor oath required. For personal study only.

✦ Synopsis

Diffusion Monte Carlo (DMC) is a random walk computational method for solving the ground-state Schrodinger equation for atoms or molecules. One obtains a biased simulated energy which is used to estimate the exact energy, where the bias increases with the time step used in the simulation. We present six new DMC algorithms, all of which have the same theoretical justification. Yet, when applied to the LiH and H2 molecules, the algorithms give results with markedly different error. Furthermore, algorithms which exhibit a small error when applied to one molecule show significantly greater error for the other. "he explanation for these results relates to sampling of configuration space in the neighborhood of the nuclei. We investigate this issue hoping that our results will aid in the design of more efficient DMC algorithms.

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