A ninedimensional ab initio global potential energy surface for the H{sub 2}O{sup +} + H{sub 2} → H{sub 3}O{sup +} + H reaction
Abstract
An accurate fulldimensional global potential energy surface (PES) is developed for the title reaction. While the longrange interactions in the reactant asymptote are represented by an analytical expression, the interaction region of the PES is fit to more than 81 000 of ab initio points at the UCCSD(T)F12b/AVTZ level using the permutation invariant polynomial neural network approach. Fully symmetric with respect to permutation of all four hydrogen atoms, the PES provides a faithful representation of the ab initio points, with a root mean square error of 1.8 meV or 15 cm{sup −1}. The reaction path for this exoergic reaction features an attractive and barrierless entrance channel, a submerged saddle point, a shallow H{sub 4}O{sup +} well, and a barrierless exit channel. The rate coefficients for the title reaction and kinetic isotope effect have been determined on this PES using quasiclassical trajectories, and they are in good agreement with available experimental data. It is further shown that the H{sub 2}O{sup +} rotational enhancement of reactivity observed experimentally can be traced to the submerged saddle point. Using our recently proposed Sudden Vector Projection model, we demonstrate that a rotational degree of freedom of the H{sub 2}O{sup +} reactant is strongly coupled with themore »
 Authors:
 Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States)
 Publication Date:
 OSTI Identifier:
 22420101
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; DEGREES OF FREEDOM; HYDROGEN; INTERACTION RANGE; INTERACTIONS; ISOTOPE EFFECTS; MEV RANGE; OXONIUM IONS; POLYNOMIALS; POTENTIAL ENERGY; SURFACES; WATER
Citation Formats
Li, Anyang, and Guo, Hua, Email: hguo@unm.edu. A ninedimensional ab initio global potential energy surface for the H{sub 2}O{sup +} + H{sub 2} → H{sub 3}O{sup +} + H reaction. United States: N. p., 2014.
Web. doi:10.1063/1.4881943.
Li, Anyang, & Guo, Hua, Email: hguo@unm.edu. A ninedimensional ab initio global potential energy surface for the H{sub 2}O{sup +} + H{sub 2} → H{sub 3}O{sup +} + H reaction. United States. doi:10.1063/1.4881943.
Li, Anyang, and Guo, Hua, Email: hguo@unm.edu. Sat .
"A ninedimensional ab initio global potential energy surface for the H{sub 2}O{sup +} + H{sub 2} → H{sub 3}O{sup +} + H reaction". United States.
doi:10.1063/1.4881943.
@article{osti_22420101,
title = {A ninedimensional ab initio global potential energy surface for the H{sub 2}O{sup +} + H{sub 2} → H{sub 3}O{sup +} + H reaction},
author = {Li, Anyang and Guo, Hua, Email: hguo@unm.edu},
abstractNote = {An accurate fulldimensional global potential energy surface (PES) is developed for the title reaction. While the longrange interactions in the reactant asymptote are represented by an analytical expression, the interaction region of the PES is fit to more than 81 000 of ab initio points at the UCCSD(T)F12b/AVTZ level using the permutation invariant polynomial neural network approach. Fully symmetric with respect to permutation of all four hydrogen atoms, the PES provides a faithful representation of the ab initio points, with a root mean square error of 1.8 meV or 15 cm{sup −1}. The reaction path for this exoergic reaction features an attractive and barrierless entrance channel, a submerged saddle point, a shallow H{sub 4}O{sup +} well, and a barrierless exit channel. The rate coefficients for the title reaction and kinetic isotope effect have been determined on this PES using quasiclassical trajectories, and they are in good agreement with available experimental data. It is further shown that the H{sub 2}O{sup +} rotational enhancement of reactivity observed experimentally can be traced to the submerged saddle point. Using our recently proposed Sudden Vector Projection model, we demonstrate that a rotational degree of freedom of the H{sub 2}O{sup +} reactant is strongly coupled with the reaction coordinate at this saddle point, thus unraveling the origin of the pronounced mode specificity in this reaction.},
doi = {10.1063/1.4881943},
journal = {Journal of Chemical Physics},
number = 22,
volume = 140,
place = {United States},
year = {Sat Jun 14 00:00:00 EDT 2014},
month = {Sat Jun 14 00:00:00 EDT 2014}
}

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