Size-consistent variational approaches to nonlocal pseudopotentials: Standard and lattice regularized diffusion Monte Carlo methods revisted

Michele Casula, Saverio Moroni, Sandro Sorella, Claudia Filippi

Research output: Contribution to journalArticleAcademicpeer-review

69 Citations (Scopus)

Abstract

We propose improved versions of the standard diffusion Monte Carlo (DMC) and the lattice regularized diffusion Monte Carlo (LRDMC) algorithms. For the DMC method, we refine a scheme recently devised to treat nonlocal pseudopotential in a variational way. We show that such scheme—when applied to large enough systems—maintains its effectiveness only at correspondingly small enough time-steps, and we present two simple upgrades of the method which guarantee the variational property in a size-consistent manner. For the LRDMC method, which is size-consistent and variational by construction, we enhance the computational efficiency by introducing: (i) an improved definition of the effective lattice Hamiltonian which remains size-consistent and entails a small lattice-space error with a known leading term and (ii) a new randomization method for the positions of the lattice knots which requires a single lattice-space
Original languageUndefined
Pages (from-to)154113-1-154113-9
Number of pages9
JournalJournal of chemical physics
Volume132
Issue number15
DOIs
Publication statusPublished - 2010

Keywords

  • IR-76316
  • METIS-266191

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