David M. Lauvergnat
Fast vibrational configuration interaction using generalized curvilinear coordinates and self-consistent basis
Lauvergnat, David M.; Scribano, Yohann; Benoit, David M.
Dr David Benoit D.Benoit@hull.ac.uk
Senior Lecturer in Molecular Physics and Astrochemistry
In this paper, we couple a numerical kinetic-energy operator approach to the direct-vibrational self-consistent field (VSCF)/vibrational configuration interaction (VCI) method for the calculation of vibrational anharmonic frequencies. By combining this with fast-VSCF, an efficient direct evaluation of the ab initio potential-energy surface (PES), we introduce a general formalism for the computation of vibrational bound states of molecular systems exhibiting large-amplitude motion such as methyl-group torsion. We validate our approach on an analytical two-dimensional model and apply it to the methanol molecule. We show that curvilinear coordinates lead to a significant improvement in the VSCF/VCI description of the torsional frequency in methanol, even for a simple two-mode coupling expansion of the PES. Moreover, we demonstrate that a curvilinear formulation of the fast-VSCF/VCI scheme improves its speed by a factor of two and its accuracy by a factor of 3.
Scribano, Y., Lauvergnat, D. M., & Benoit, D. M. (2010). Fast vibrational configuration interaction using generalized curvilinear coordinates and self-consistent basis. The Journal of chemical physics, 133(9), 094103 - 0. https://doi.org/10.1063/1.3476468
|Journal Article Type||Article|
|Acceptance Date||Jul 1, 2010|
|Online Publication Date||Sep 1, 2010|
|Publication Date||Sep 7, 2010|
|Journal||JOURNAL OF CHEMICAL PHYSICS|
|Peer Reviewed||Peer Reviewed|
|Article Number||ARTN 094103|
|Pages||094103 - 0|
|Keywords||Ab initio calculations; Configuration interactions; Librational states; Organic compounds; SCF calculations; Vibrational states; Large-amplitude vibrations; Kinetic-energy operators; Bound-state eigenvalues; Ab initio potential-energy; Grid hamiltonian me|
This file is under embargo due to copyright reasons.
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