Research output: Contribution to journal › Article › peer-review
Relativistic fock space coupled cluster method for many-electron systems : Non-perturbative account for connected triple excitations. / Oleynichenko, Alexander V.; Zaitsevskii, Andréi; Skripnikov, Leonid V.; Eliav, Ephraim.
In: Symmetry, Vol. 12, No. 7, 1101, 07.2020.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Relativistic fock space coupled cluster method for many-electron systems
T2 - Non-perturbative account for connected triple excitations
AU - Oleynichenko, Alexander V.
AU - Zaitsevskii, Andréi
AU - Skripnikov, Leonid V.
AU - Eliav, Ephraim
N1 - Publisher Copyright: © 2020 by the authors.
PY - 2020/7
Y1 - 2020/7
N2 - The Fock space relativistic coupled cluster method (FS-RCC) is one of the most promising tools of electronic structure modeling for atomic and molecular systems containing heavy nuclei. Until recently, capabilities of the FS-RCC method were severely restricted by the fact that only single and double excitations in the exponential parametrization of the wave operator were considered. We report the design and the first computer implementation of FS-RCC schemes with full and simplified non-perturbative account for triple excitations in the cluster operator. Numerical stability of the new computational scheme and thus its applicability to a wide variety of molecular electronic states is ensured using the dynamic shift technique combined with the extrapolation to zero-shift limit. Pilot applications to atomic (Tl, Pb) and molecular (TlH) systems reported in the paper indicate that the breakthrough in accuracy and predictive power of the electronic structure calculations for heavy-element compounds can be achieved. Moreover, the described approach can provide a firm basis for high-precision modeling of heavy molecular systems with several open shells, including actinide compounds.
AB - The Fock space relativistic coupled cluster method (FS-RCC) is one of the most promising tools of electronic structure modeling for atomic and molecular systems containing heavy nuclei. Until recently, capabilities of the FS-RCC method were severely restricted by the fact that only single and double excitations in the exponential parametrization of the wave operator were considered. We report the design and the first computer implementation of FS-RCC schemes with full and simplified non-perturbative account for triple excitations in the cluster operator. Numerical stability of the new computational scheme and thus its applicability to a wide variety of molecular electronic states is ensured using the dynamic shift technique combined with the extrapolation to zero-shift limit. Pilot applications to atomic (Tl, Pb) and molecular (TlH) systems reported in the paper indicate that the breakthrough in accuracy and predictive power of the electronic structure calculations for heavy-element compounds can be achieved. Moreover, the described approach can provide a firm basis for high-precision modeling of heavy molecular systems with several open shells, including actinide compounds.
KW - Excited states
KW - Heavy-element compounds
KW - High-precision electronic structure modeling
KW - Relativistic coupled cluster method
KW - HIGH SECTORS
KW - heavy-element compounds
KW - MODEL
KW - BODY PERTURBATION-THEORY
KW - INTERMEDIATE HAMILTONIAN-FORMULATION
KW - high-precision electronic structure modeling
KW - relativistic coupled cluster method
KW - excited states
KW - THALLIUM
KW - CHEMISTRY
KW - INCLUSION
KW - BASIS-SETS
KW - SPECTRUM
KW - HILBERT-SPACE
UR - http://www.scopus.com/inward/record.url?scp=85088597129&partnerID=8YFLogxK
UR - https://www.mendeley.com/catalogue/5f9fb9ff-0a02-317e-ab5f-3816443efac1/
U2 - 10.3390/sym12071101
DO - 10.3390/sym12071101
M3 - Article
AN - SCOPUS:85088597129
VL - 12
JO - Symmetry
JF - Symmetry
SN - 2073-8994
IS - 7
M1 - 1101
ER -
ID: 61033562