Relativistic unitary coupled cluster method for ground-state molecular properties
Abstract
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.
Cite
@article{arxiv.2510.18709,
title = {Relativistic unitary coupled cluster method for ground-state molecular properties},
author = {Kamal Majee and Somesh Chamoli and Malaya K. Nayak and Achintya Kumar Dutta},
journal= {arXiv preprint arXiv:2510.18709},
year = {2026}
}
Comments
12 pages, 4 figures, 4 tables