PMID- 30579315
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20181228
LR  - 20181228
IS  - 1089-7690 (Electronic)
IS  - 0021-9606 (Linking)
VI  - 149
IP  - 23
DP  - 2018 Dec 21
TI  - Non-orthogonal determinants in multi-Slater-Jastrow trial wave functions for 
      fixed-node diffusion Monte Carlo.
PG  - 234104
LID - 10.1063/1.5052906 [doi]
AB  - The accuracy and efficiency of ab initio Quantum Monte Carlo (QMC) algorithms 
      benefit greatly from compact variational trial wave functions that accurately 
      reproduce ground state properties of a system. We investigate the possibility of 
      using multi-Slater-Jastrow trial wave functions with non-orthogonal determinants 
      by optimizing identical single particle orbitals independently in separate 
      determinants. As a test case, we compute variational and fixed-node diffusion 
      Monte Carlo (FN-DMC) energies of a C(2) molecule. For a given multi-determinant 
      expansion, we find that this non-orthogonal orbital optimization results in a 
      consistent improvement in the variational energy and the FN-DMC energy on the 
      order of a few tenths of an eV. In some cases, fewer non-orthogonal determinants 
      are required compared to orthogonal ones in order to achieve similar accuracy in 
      FN-DMC. Our calculations indicate that trial wave functions with non-orthogonal 
      determinants can improve computed energies in a QMC calculation when compared to 
      their orthogonal counterparts.
FAU - Pathak, Shivesh
AU  - Pathak S
AD  - Department of Physics, University of Illinois at Urbana-Champaign, Urbana, 
      Illinois 61801-3028, USA.
FAU - Wagner, Lucas K
AU  - Wagner LK
AUID- ORCID: 000000023755044X
AD  - Department of Physics, University of Illinois at Urbana-Champaign, Urbana, 
      Illinois 61801-3028, USA.
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Chem Phys
JT  - The Journal of chemical physics
JID - 0375360
EDAT- 2018/12/24 06:00
MHDA- 2018/12/24 06:01
CRDT- 2018/12/24 06:00
PHST- 2018/12/24 06:00 [entrez]
PHST- 2018/12/24 06:00 [pubmed]
PHST- 2018/12/24 06:01 [medline]
AID - 10.1063/1.5052906 [doi]
PST - ppublish
SO  - J Chem Phys. 2018 Dec 21;149(23):234104. doi: 10.1063/1.5052906.