David M. Lauvergnat
Fast vibrational configuration interaction using generalized curvilinear coordinates and self-consistent basis
Lauvergnat, David M.; Scribano, Yohann; Benoit, David M.
Authors
Yohann Scribano
Dr David Benoit D.Benoit@hull.ac.uk
Senior Lecturer in Molecular Physics and Astrochemistry
Abstract
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.
Citation
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 |
Print ISSN | 0021-9606 |
Electronic ISSN | 1089-7690 |
Publisher | American Institute of Physics |
Peer Reviewed | Peer Reviewed |
Volume | 133 |
Issue | 9 |
Article Number | ARTN 094103 |
Pages | 094103 - 0 |
DOI | https://doi.org/10.1063/1.3476468 |
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 |
Public URL | https://hull-repository.worktribe.com/output/399986 |
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