Revealing the regularities of electron correlation energies associated with valence electrons in atoms in the first three rows of the periodic table

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Auteurs principaux: Hai, G. -Q., Cândido, L., Brito, B. G. A., Liu, Y.
Format: Preprint
Publié: 2024
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author Hai, G. -Q.
Cândido, L.
Brito, B. G. A.
Liu, Y.
author_facet Hai, G. -Q.
Cândido, L.
Brito, B. G. A.
Liu, Y.
contents Electronic correlation is a complex many-body effect and the correlation energy depends on the specific electronic structure and spatial distribution of electrons in each atom and molecule. Although the total correlation energy in an atom can be decomposed into different components such as inter-orbital and intra-orbital pair-correlation energies (PCE), it is generally believed that the PCEs in different atoms cannot be the same. In this work, we investigate the correlation energies of the atoms in the first three rows of the periodic table (He to Ar). It is found that when the correlation energy is defined as the difference between the exact ground-state energy and the unrestricted Hartree-Fock (UHF) energy, the inter- and intra-orbital PECs associated with the valence electrons of the atoms in the same row of the periodic table have the same values. These PCEs are not entangled and their values depend only on the electron orbitals. For two specific orbitals, the inter-orbital correlation energy is the same between two electrons of parallel spins or anti-parallel spins. We also show that the effects of orbital relaxation on the correlation energy are surprisingly small.
format Preprint
id arxiv_https___arxiv_org_abs_2404_16759
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Revealing the regularities of electron correlation energies associated with valence electrons in atoms in the first three rows of the periodic table
Hai, G. -Q.
Cândido, L.
Brito, B. G. A.
Liu, Y.
Chemical Physics
Strongly Correlated Electrons
Electronic correlation is a complex many-body effect and the correlation energy depends on the specific electronic structure and spatial distribution of electrons in each atom and molecule. Although the total correlation energy in an atom can be decomposed into different components such as inter-orbital and intra-orbital pair-correlation energies (PCE), it is generally believed that the PCEs in different atoms cannot be the same. In this work, we investigate the correlation energies of the atoms in the first three rows of the periodic table (He to Ar). It is found that when the correlation energy is defined as the difference between the exact ground-state energy and the unrestricted Hartree-Fock (UHF) energy, the inter- and intra-orbital PECs associated with the valence electrons of the atoms in the same row of the periodic table have the same values. These PCEs are not entangled and their values depend only on the electron orbitals. For two specific orbitals, the inter-orbital correlation energy is the same between two electrons of parallel spins or anti-parallel spins. We also show that the effects of orbital relaxation on the correlation energy are surprisingly small.
title Revealing the regularities of electron correlation energies associated with valence electrons in atoms in the first three rows of the periodic table
topic Chemical Physics
Strongly Correlated Electrons
url https://arxiv.org/abs/2404.16759