Please use this identifier to cite or link to this item: http://hdl.handle.net/2248/6830
Title: Relativistic state-specific multireference perturbation theory incorporating improved virtual orbitals: application to the ground state single-bond dissociation
Authors: Ghosh, A
Chaudhuri, R. K
Chattopadhyay, S
Mahapatra, U. S
Keywords: Four-component relativistic spinors;SSMRPT;IVO-CASCI;Diatomic halogens;Alkali dimers;Full dissociation energy curves;Spectroscopic constants
Issue Date: 5-Oct-2015
Publisher: John Wiley & Sons
Citation: Journal of Computational Chemistry, Vol. 36, No. 26, pp. 1954-1972
Abstract: 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 Li2, Na2, K2, Rb2, F2, Cl2, and Br2 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.
Description: Restricted Access
URI: http://hdl.handle.net/2248/6830
ISSN: 0192-8651
???metadata.dc.rights???: © John Wiley & Sons
???metadata.dc.relation.uri???: http://dx.doi.org/10.1002/jcc.24037
Appears in Collections:IIAP Publications



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