Relativistic state-specific multireference perturbation theory incorporating improved virtual orbitals Application to the ground state single-bond dissociation

Relativistic state-specific multireference perturbation theory incorporating improved virtual orbitals : Application to the ground state single-bond dissociation

© 2015 Wiley Periodicals, Inc.

Bibliographische Detailangaben
Veröffentlicht in:Journal of computational chemistry. - 1984. - 36(2015), 26 vom: 05. Okt., Seite 1954-72
1. Verfasser: Ghosh, Anirban (VerfasserIn)
Weitere Verfasser: Chaudhuri, Rajat K, Chattopadhyay, Sudip, Mahapatra, Uttam Sinha
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2015
Zugriff auf das übergeordnete Werk:Journal of computational chemistry
Schlagworte:Journal Article IVO-CASCI SSMRPT alkali dimers diatomic halogens four-component relativistic spinors full dissociation energy curves spectroscopic constants
Beschreibung
Zusammenfassung:© 2015 Wiley Periodicals, Inc.
Using four-component (4c) relativistic spinors, we present a computationally economical relativistic ab initio method for molecular systems employing our recently proposed second-order state-specific multireference perturbation theory (SSMRPT) incorporating the improved virtual orbital-complete active space configuration interaction (IVO-CASCI) reference wavefunction. The resulting method, 4c-IVO-SSMRPT [calculate one state at a time] is tested in pilot calculations on the homonuclear dimers including Li(2), Na(2), K(2), Rb(2), F(2), Cl(2), and Br(2) through the computations of the ground state potential energy curves (PECs). As SSMRPT curbs intruder effects, 4c-IVO-SSMRPT is numerically stable. To our knowledge, the SSMRPT in the 4c relativistic framework has not been explored in the past. Selective spectroscopic constants that are closely related to the correct shape and accuracy of the energy surfaces have been extracted from the computed PECs. For the halogen molecules, a relativistic destabilization of the bond has been found. Relativistic and electron correlation effects need to be incorporated to get reliable estimates. Our results are in good accordance with reference theoretical and experimental data which manifests the computational accuracy and efficiency of the new 4c-IVO-SSMRPT method. The method opens for an improved description of MR systems containing heavy elements. The inexpensiveness of IVO-CASCI makes 4c-IVO-SSMRPT method promising for studies on large systems of heavy elements
Beschreibung:Date Completed 08.12.2015
Date Revised 05.09.2015
published: Print-Electronic
Citation Status PubMed-not-MEDLINE
ISSN:1096-987X
DOI:10.1002/jcc.24037