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Main Authors: Shaikh, Aqsa, Madany, Omar, Kincaid, Benjamin, Mitas, Lubos
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2512.17063
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author Shaikh, Aqsa
Madany, Omar
Kincaid, Benjamin
Mitas, Lubos
author_facet Shaikh, Aqsa
Madany, Omar
Kincaid, Benjamin
Mitas, Lubos
contents We employ correlation-consistent effective core potentials (ccECPs) to perform exact or nearly exact correlation and total energy calculations for the fifth-row elements (Rb-Xe). Total energies are calculated using various correlated methods: configuration interaction (CI), coupled-cluster (CC) up to perturbative quadruple excitations whenever feasible, and stochastic quantum Monte Carlo (QMC) approaches. In order to estimate the energy at the complete basis set (CBS) limit, the basis sets are constructed systematically through aug-cc-p(C)VnZ for each ccECP and further extrapolated to the CBS limit within the corresponding methods. Kinetic energies are evaluated at the FCI/CISD level to provide insights into the electron density and localization of the ccECPs. We also provide data sets for widely used diffusion Monte Carlo (DMC) to quantify fixed-node biases with single-reference trial wavefunctions. These comprehensive benchmarks validate the accuracy of ccECPs within the CC, CI, and QMC methodologies, thus providing accurate and tested valence-only Hamiltonians for many-body electronic structure calculations.
format Preprint
id arxiv_https___arxiv_org_abs_2512_17063
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Accurate atomic correlation and total energies for correlation consistent effective core potentials II: Rb-Xe elements
Shaikh, Aqsa
Madany, Omar
Kincaid, Benjamin
Mitas, Lubos
Materials Science
Chemical Physics
Computational Physics
We employ correlation-consistent effective core potentials (ccECPs) to perform exact or nearly exact correlation and total energy calculations for the fifth-row elements (Rb-Xe). Total energies are calculated using various correlated methods: configuration interaction (CI), coupled-cluster (CC) up to perturbative quadruple excitations whenever feasible, and stochastic quantum Monte Carlo (QMC) approaches. In order to estimate the energy at the complete basis set (CBS) limit, the basis sets are constructed systematically through aug-cc-p(C)VnZ for each ccECP and further extrapolated to the CBS limit within the corresponding methods. Kinetic energies are evaluated at the FCI/CISD level to provide insights into the electron density and localization of the ccECPs. We also provide data sets for widely used diffusion Monte Carlo (DMC) to quantify fixed-node biases with single-reference trial wavefunctions. These comprehensive benchmarks validate the accuracy of ccECPs within the CC, CI, and QMC methodologies, thus providing accurate and tested valence-only Hamiltonians for many-body electronic structure calculations.
title Accurate atomic correlation and total energies for correlation consistent effective core potentials II: Rb-Xe elements
topic Materials Science
Chemical Physics
Computational Physics
url https://arxiv.org/abs/2512.17063