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Title: Fitting coupled potential energy surfaces for large systems: Method and construction of a 3-state representation for phenol photodissociation in the full 33 internal degrees of freedom using multireference configuration interaction determined data

Abstract

A recently reported algorithm for representing adiabatic states coupled by conical intersections using a quasi-diabatic state Hamiltonian in four and five atom systems is extended to treat nonadiabatic processes in considerably larger molecules. The method treats all internal degrees of freedom and uses electronic structure data from ab initio multireference configuration interaction wave functions with nuclear configuration selection based on quasi-classical surface hopping trajectories. The method is shown here to be able to treat ∼30 internal degrees of freedom including dissociative and large amplitude internal motion. Two procedures are introduced which are essential to the algorithm, a null space projector which removes basis functions from the fitting process until they are needed and a partial diagonalization technique which allows for automated, but accurate, treatment of the vicinity of extended seams of conical intersections of two or more states. These procedures are described in detail. The method is illustrated using the photodissociaton of phenol, C{sub 6}H{sub 5}OH(X{sup ~1}A{sup ′}) + hv → C{sub 6}H{sub 5}OH(A{sup ~1}A{sup ′}, B{sup ~1}A{sup ′′}) → C{sub 6}H{sub 5}O(X{sup ~2}B{sub 1}, A{sup ~2}B{sub 2}) + H as a test case. Ab initio electronic structure data for the 1,2,3{sup 1}A states of phenol, which are coupled bymore » conical intersections, are obtained from multireference first order configuration interaction wave functions. The design of bases to simultaneously treat large amplitude motion and dissociation is described, as is the ability of the fitting procedure to smooth the irregularities in the electronic energies attributable to the orbital changes that are inherent to nonadiabatic processes.« less

Authors:
Publication Date:
OSTI Identifier:
22253598
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 140; Journal Issue: 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALGORITHMS; AMPLITUDES; CONFIGURATION INTERACTION; DEGREES OF FREEDOM; DISSOCIATION; ELECTRONIC STRUCTURE; HAMILTONIANS; PHENOL; PHOTOLYSIS; POTENTIAL ENERGY; WAVE FUNCTIONS

Citation Formats

Zhu, Xiaolei, and Yarkony, David R., E-mail: yarkony@jhu.edu. Fitting coupled potential energy surfaces for large systems: Method and construction of a 3-state representation for phenol photodissociation in the full 33 internal degrees of freedom using multireference configuration interaction determined data. United States: N. p., 2014. Web. doi:10.1063/1.4857335.
Zhu, Xiaolei, & Yarkony, David R., E-mail: yarkony@jhu.edu. Fitting coupled potential energy surfaces for large systems: Method and construction of a 3-state representation for phenol photodissociation in the full 33 internal degrees of freedom using multireference configuration interaction determined data. United States. https://doi.org/10.1063/1.4857335
Zhu, Xiaolei, and Yarkony, David R., E-mail: yarkony@jhu.edu. 2014. "Fitting coupled potential energy surfaces for large systems: Method and construction of a 3-state representation for phenol photodissociation in the full 33 internal degrees of freedom using multireference configuration interaction determined data". United States. https://doi.org/10.1063/1.4857335.
@article{osti_22253598,
title = {Fitting coupled potential energy surfaces for large systems: Method and construction of a 3-state representation for phenol photodissociation in the full 33 internal degrees of freedom using multireference configuration interaction determined data},
author = {Zhu, Xiaolei and Yarkony, David R., E-mail: yarkony@jhu.edu},
abstractNote = {A recently reported algorithm for representing adiabatic states coupled by conical intersections using a quasi-diabatic state Hamiltonian in four and five atom systems is extended to treat nonadiabatic processes in considerably larger molecules. The method treats all internal degrees of freedom and uses electronic structure data from ab initio multireference configuration interaction wave functions with nuclear configuration selection based on quasi-classical surface hopping trajectories. The method is shown here to be able to treat ∼30 internal degrees of freedom including dissociative and large amplitude internal motion. Two procedures are introduced which are essential to the algorithm, a null space projector which removes basis functions from the fitting process until they are needed and a partial diagonalization technique which allows for automated, but accurate, treatment of the vicinity of extended seams of conical intersections of two or more states. These procedures are described in detail. The method is illustrated using the photodissociaton of phenol, C{sub 6}H{sub 5}OH(X{sup ~1}A{sup ′}) + hv → C{sub 6}H{sub 5}OH(A{sup ~1}A{sup ′}, B{sup ~1}A{sup ′′}) → C{sub 6}H{sub 5}O(X{sup ~2}B{sub 1}, A{sup ~2}B{sub 2}) + H as a test case. Ab initio electronic structure data for the 1,2,3{sup 1}A states of phenol, which are coupled by conical intersections, are obtained from multireference first order configuration interaction wave functions. The design of bases to simultaneously treat large amplitude motion and dissociation is described, as is the ability of the fitting procedure to smooth the irregularities in the electronic energies attributable to the orbital changes that are inherent to nonadiabatic processes.},
doi = {10.1063/1.4857335},
url = {https://www.osti.gov/biblio/22253598}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 2,
volume = 140,
place = {United States},
year = {Tue Jan 14 00:00:00 EST 2014},
month = {Tue Jan 14 00:00:00 EST 2014}
}