Equation-of-motion coupled-cluster theory based on the 4-component Dirac-Coulomb(-Gaunt) Hamiltonian: Energies for single electron detachment, attachment, and electronically excited states

Avijit Shee, Trond Saue, Lucas Visscher, André Severo Pereira Gomes*

*Corresponding author for this work

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Abstract

We report in this paper an implementation of a 4-component relativistic Hamiltonian based Equation-of-Motion Coupled-Cluster with singles and doubles (EOM-CCSD) theory for the calculation of ionization potential, electron affinity, and excitation energy. In this work, we utilize the previously developed double group symmetry-based generalized tensor contraction scheme and also extend it in order to carry out tensor contractions involving non-totally symmetric and odd-ranked tensors. Several approximated spin-free and two-component Hamiltonians can also be accessed in this implementation. We have applied this method to the halogen monoxide (XO, X = Cl, Br, I, At, Ts) species, in order to assess the quality of a few other recent EOM-CCSD implementations, where spin-orbit coupling contribution has been approximated in different degrees. Besides, we have also studied various excited states of CH2IBr, CH2I2, and I3- (as well as single electron attachment and detachment electronic states of the same species) where comparison has been made with a closely related multi-reference coupled-cluster method, namely, Intermediate Hamiltonian Fock Space Coupled-Cluster singles and doubles theory.

Original languageEnglish
Article number174113
Pages (from-to)1-19
Number of pages19
JournalJournal of Chemical Physics
Volume149
Issue number17
DOIs
Publication statusPublished - 7 Nov 2018

Funding

The members of the PhLAM laboratory acknowledge support from the CaPPA project (Chemical and Physical Properties of the Atmosphere) funded by the French National Research Agency (ANR) through the PIA (Programme d’Investissement d’Avenir) under Contract No. “ANR-11-LABX-0005-01” as well as by the Ministry of Higher Education and Research, Hauts de France council and European Regional Development Fund (ERDF) through the Contrat de Projets Etat-Region (CPER) CLIMBIO (Changement clima-tique, dynamique de l’atmosphère, impacts sur la biodiversité et la santé humaine). Furthermore, ASPG acknowledges funding from the CNRS Institute of Physics (INP) via the PICS program (Grant No. 6386) and computational time provided by the French national supercomputing facilities (Grant Nos. DARI x2016081859, A0010801859, and A0030801859), and both A.S. and A.S.P.G. acknowledge many illuminating discussions on the implementation of the matrix-free diagonalization method with Dr. Jean-Pierre Flament (PhLAM).

FundersFunder number
CNRS Institute of Physics
INP6386
Ministry of Higher Education and Research, Hauts de France council
Agence Nationale de la RechercheANR-11-LABX-0005-01
European Regional Development Fund

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