Relativistic unitary coupled cluster method for ground-state molecular properties

Fuente: arXiv
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Main Authors: Majee, Kamal, Chamoli, Somesh, Nayak, Malaya K., Dutta, Achintya Kumar
Format: Preprint
Published: 2025
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author Majee, Kamal
Chamoli, Somesh
Nayak, Malaya K.
Dutta, Achintya Kumar
author_facet Majee, Kamal
Chamoli, Somesh
Nayak, Malaya K.
Dutta, Achintya Kumar
contents We propose a relativistic unitary coupled cluster (UCC) expectation value approach for computing first-order properties of heavy-element systems. Both perturbative (UCC3) and non-perturbative (qUCC) commutator-based formulations are applied to evaluate ground-state properties, including the permanent dipole moment (PDM), magnetic hyperfine structure (HFS) constant, and electric field gradient (EFG). The results are compared with available experimental data and those from conventional coupled cluster (CC) calculations. The non-perturbative commutator-based approach truncated at the singles and doubles level (qUCCSD) exhibits markedly better agreement with both CCSD and experiment than the perturbative UCC3 method, likely due to its improved treatment of relaxation effects.
format Preprint
id arxiv_https___arxiv_org_abs_2510_18709
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Relativistic unitary coupled cluster method for ground-state molecular properties
Majee, Kamal
Chamoli, Somesh
Nayak, Malaya K.
Dutta, Achintya Kumar
Chemical Physics
We propose a relativistic unitary coupled cluster (UCC) expectation value approach for computing first-order properties of heavy-element systems. Both perturbative (UCC3) and non-perturbative (qUCC) commutator-based formulations are applied to evaluate ground-state properties, including the permanent dipole moment (PDM), magnetic hyperfine structure (HFS) constant, and electric field gradient (EFG). The results are compared with available experimental data and those from conventional coupled cluster (CC) calculations. The non-perturbative commutator-based approach truncated at the singles and doubles level (qUCCSD) exhibits markedly better agreement with both CCSD and experiment than the perturbative UCC3 method, likely due to its improved treatment of relaxation effects.
title Relativistic unitary coupled cluster method for ground-state molecular properties
topic Chemical Physics
url https://arxiv.org/abs/2510.18709