PMID- 33167659
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20201110
IS  - 1089-7690 (Electronic)
IS  - 0021-9606 (Linking)
VI  - 153
IP  - 17
DP  - 2020 Nov 7
TI  - Taming the fixed-node error in diffusion Monte Carlo via range separation.
PG  - 174107
LID - 10.1063/5.0026324 [doi]
AB  - By combining density-functional theory (DFT) and wave function theory via the 
      range separation (RS) of the interelectronic Coulomb operator, we obtain accurate 
      fixed-node diffusion Monte Carlo (FN-DMC) energies with compact multi-determinant 
      trial wave functions. In particular, we combine here short-range 
      exchange-correlation functionals with a flavor of selected configuration 
      interaction known as configuration interaction using a perturbative selection 
      made iteratively (CIPSI), a scheme that we label RS-DFT-CIPSI. One of the 
      take-home messages of the present study is that RS-DFT-CIPSI trial wave functions 
      yield lower fixed-node energies with more compact multi-determinant expansions 
      than CIPSI, especially for small basis sets. Indeed, as the CIPSI component of 
      RS-DFT-CIPSI is relieved from describing the short-range part of the correlation 
      hole around the electron-electron coalescence points, the number of determinants 
      in the trial wave function required to reach a given accuracy is significantly 
      reduced as compared to a conventional CIPSI calculation. Importantly, by 
      performing various numerical experiments, we evidence that the RS-DFT scheme 
      essentially plays the role of a simple Jastrow factor by mimicking short-range 
      correlation effects, hence avoiding the burden of performing a stochastic 
      optimization. Considering the 55 atomization energies of the Gaussian-1 benchmark 
      set of molecules, we show that using a fixed value of mu = 0.5 bohr(-1) provides 
      effective error cancellations as well as compact trial wave functions, making the 
      present method a good candidate for the accurate description of large chemical 
      systems.
FAU - Scemama, Anthony
AU  - Scemama A
AUID- ORCID: 0000000349557136
AD  - Laboratoire de Chimie et Physique Quantiques (UMR 5626), Universite de Toulouse, 
      CNRS, UPS, Toulouse, France.
FAU - Giner, Emmanuel
AU  - Giner E
AUID- ORCID: 0000000262061103
AD  - Laboratoire de Chimie Theorique (UMR 7616), Sorbonne Universite, CNRS, Paris, 
      France.
FAU - Benali, Anouar
AU  - Benali A
AUID- ORCID: 0000000221330338
AD  - Computational Science Division, Argonne National Laboratory, Argonne, Illinois 
      60439, USA.
FAU - Loos, Pierre-Francois
AU  - Loos PF
AUID- ORCID: 0000000305987425
AD  - Laboratoire de Chimie et Physique Quantiques (UMR 5626), Universite de Toulouse, 
      CNRS, UPS, Toulouse, France.
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Chem Phys
JT  - The Journal of chemical physics
JID - 0375360
SB  - IM
EDAT- 2020/11/11 06:00
MHDA- 2020/11/11 06:01
CRDT- 2020/11/10 05:30
PHST- 2020/11/10 05:30 [entrez]
PHST- 2020/11/11 06:00 [pubmed]
PHST- 2020/11/11 06:01 [medline]
AID - 10.1063/5.0026324 [doi]
PST - ppublish
SO  - J Chem Phys. 2020 Nov 7;153(17):174107. doi: 10.1063/5.0026324.