Neural network variational Monte Carlo for positronic chemistry

Fuente: arXiv
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Main Authors: Cassella, G., Foulkes, W. M. C., Pfau, D., Spencer, J. S.
Format: Preprint
Published: 2023
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author Cassella, G.
Foulkes, W. M. C.
Pfau, D.
Spencer, J. S.
author_facet Cassella, G.
Foulkes, W. M. C.
Pfau, D.
Spencer, J. S.
contents Quantum chemical calculations of the ground-state properties of positron-molecule complexes are challenging. The main difficulty lies in employing an appropriate basis set for representing the coalescence between electrons and a positron. Here, we tackle this problem with the recently developed Fermionic neural network (FermiNet) wavefunction, which does not depend on a basis set. We find that FermiNet produces highly accurate, in some cases state-of-the-art, ground-state energies across a range of atoms and small molecules with a wide variety of qualitatively distinct positron binding characteristics. We calculate the binding energy of the challenging non-polar benzene molecule, finding good agreement with the experimental value, and obtain annihilation rates which compare favourably with those obtained with explicitly correlated Gaussian wavefunctions. Our results demonstrate a generic advantage of neural network wavefunction-based methods and broaden their applicability to systems beyond the standard molecular Hamiltonian.
format Preprint
id arxiv_https___arxiv_org_abs_2310_05607
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Neural network variational Monte Carlo for positronic chemistry
Cassella, G.
Foulkes, W. M. C.
Pfau, D.
Spencer, J. S.
Computational Physics
Other Condensed Matter
Quantum chemical calculations of the ground-state properties of positron-molecule complexes are challenging. The main difficulty lies in employing an appropriate basis set for representing the coalescence between electrons and a positron. Here, we tackle this problem with the recently developed Fermionic neural network (FermiNet) wavefunction, which does not depend on a basis set. We find that FermiNet produces highly accurate, in some cases state-of-the-art, ground-state energies across a range of atoms and small molecules with a wide variety of qualitatively distinct positron binding characteristics. We calculate the binding energy of the challenging non-polar benzene molecule, finding good agreement with the experimental value, and obtain annihilation rates which compare favourably with those obtained with explicitly correlated Gaussian wavefunctions. Our results demonstrate a generic advantage of neural network wavefunction-based methods and broaden their applicability to systems beyond the standard molecular Hamiltonian.
title Neural network variational Monte Carlo for positronic chemistry
topic Computational Physics
Other Condensed Matter
url https://arxiv.org/abs/2310.05607