Please use this identifier to cite or link to this item: http://hdl.handle.net/2248/7237
Title: Combined complete active space configuration interaction and perturbation theory applied to conformational energy prototypes: Rotation and inversion barriers
Authors: Sinha Ray, Suvonil
Mahapatra, U. S
Chaudhuri, R. K
Chattopadhyay, S
Keywords: Multireference perturbation theory;Improved virtual orbitals;State-specific method;Torsional/Inversion surfaces;Barrier height
Issue Date: Nov-2017
Publisher: Elsevier B.V
Citation: Computational and Theoretical Chemistry, Vol. 1120, pp. 56-78
Abstract: A second-order multireference perturbation theory, termed as IVO-SSMRPT which allows the use of CASCI reference wave functions with improved virtual orbitals (IVO) for capturing static correlation and state-specific parameterization of the state-universal electronic wave function in an attempt to account for dynamic correlation has been utilized in an investigation of the torsional properties of ethylene, silaethylene, hydrogen peroxide, hydrazine, and oxalyl chloride. We also calculate the barrier to inversion of ammonia. IVO-SSMRPT is robust and useful to scan energy surfaces as it avoids the intruder-state problem, a troubling aspect of various established MRPT methods, without exploiting level-shifting or increasing the size of the active space. We find that IVO-SSMRPT with the use of a relatively small active space and basis set can be compared with recent reference estimates which are reproduced within the expected precision indicating the method is useful for the study of rotation and inversion barriers of challenging molecules.
Description: Restricted Access
URI: http://hdl.handle.net/2248/7237
ISSN: 2210271X
???metadata.dc.rights???: © Elsevier B.V.
???metadata.dc.relation.uri???: https://doi.org/10.1016/j.comptc.2017.10.003
Appears in Collections:IIAP Publications

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