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 C2 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.
Pathak, Shivesh and Wagner, Lucas K.. "Non-orthogonal determinants in multi-Slater-Jastrow trial wave functions for fixed-node diffusion Monte Carlo." Journal of Chemical Physics, vol. 149, no. 23, Dec. 2018. https://doi.org/10.1063/1.5052906
Pathak, Shivesh, & Wagner, Lucas K. (2018). Non-orthogonal determinants in multi-Slater-Jastrow trial wave functions for fixed-node diffusion Monte Carlo. Journal of Chemical Physics, 149(23). https://doi.org/10.1063/1.5052906
Pathak, Shivesh, and Wagner, Lucas K., "Non-orthogonal determinants in multi-Slater-Jastrow trial wave functions for fixed-node diffusion Monte Carlo," Journal of Chemical Physics 149, no. 23 (2018), https://doi.org/10.1063/1.5052906
@article{osti_1611136,
author = {Pathak, Shivesh and Wagner, Lucas K.},
title = {Non-orthogonal determinants in multi-Slater-Jastrow trial wave functions for fixed-node diffusion Monte Carlo},
annote = {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 C2 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.},
doi = {10.1063/1.5052906},
url = {https://www.osti.gov/biblio/1611136},
journal = {Journal of Chemical Physics},
issn = {ISSN 0021-9606},
number = {23},
volume = {149},
place = {United States},
publisher = {American Institute of Physics (AIP)},
year = {2018},
month = {12}}
Journal Article
·
Wed Jan 30 23:00:00 EST 2019
· Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory
·OSTI ID:1571973