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Title: Experimental and Theoretical Studies of the F + H–F Transition-State Region by Photodetachment of [F–H–F] -

Abstract

The transition-state (TS) region of the simplest heavy-light-heavy type of reaction, F• + H-F F-H + F•, is investigated in this work by a joint experimental and theoretical approach. Photodetaching the bifluride anion, [F…H…F]–, generates a negative ion photoelectron (NIPE) spectrum with three partially resolved bands in the electron binding energy (eBE) range of 5.4 – 7.0 eV. These bands correspond to the transition from the ground state of the anion to the electronic ground state of [F-H-F]• neutral, with associated vibrational excitations. The significant increase of eBE of the bifluride anion, relative to that of F-, reflects a hydrogen bond energy between F- and HF of 46 kcal/mol. Theoretical modeling reveals that the antisymmetric motion of H between the two F atoms, near the TS on the neutral [F-H-F]• surface, dominates the observed three bands, while the F-H-F bending, F—F symmetric stretching modes, and the couplings between them is calculated to account for the breadth of the observed spectrum. From the NIPE spectrum, a lower limit on the activation enthalpy for F• + H-F F-H + F can be estimated to be H‡ = 12 ± 2 kcal/mol, a value below that of H‡ = 14.9 kcal/mol, given bymore » our G4 calculations.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]
  1. Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MS K8-88, Richland, Washington 99352, United States
  2. Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
  3. Department of Chemistry and the Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, United States
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1411900
Report Number(s):
PNNL-SA-128287
Journal ID: ISSN 1089-5639; KC0301050
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory; Journal Volume: 121; Journal Issue: 41
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Hou, Gao-Lei, Wang, Xue-Bin, McCoy, Anne B., and Borden, Weston Thatcher. Experimental and Theoretical Studies of the F • + H–F Transition-State Region by Photodetachment of [F–H–F] -. United States: N. p., 2017. Web. doi:10.1021/acs.jpca.7b07682.
Hou, Gao-Lei, Wang, Xue-Bin, McCoy, Anne B., & Borden, Weston Thatcher. Experimental and Theoretical Studies of the F • + H–F Transition-State Region by Photodetachment of [F–H–F] -. United States. doi:10.1021/acs.jpca.7b07682.
Hou, Gao-Lei, Wang, Xue-Bin, McCoy, Anne B., and Borden, Weston Thatcher. Thu . "Experimental and Theoretical Studies of the F • + H–F Transition-State Region by Photodetachment of [F–H–F] -". United States. doi:10.1021/acs.jpca.7b07682.
@article{osti_1411900,
title = {Experimental and Theoretical Studies of the F • + H–F Transition-State Region by Photodetachment of [F–H–F] -},
author = {Hou, Gao-Lei and Wang, Xue-Bin and McCoy, Anne B. and Borden, Weston Thatcher},
abstractNote = {The transition-state (TS) region of the simplest heavy-light-heavy type of reaction, F• + H-F F-H + F•, is investigated in this work by a joint experimental and theoretical approach. Photodetaching the bifluride anion, [F…H…F]–, generates a negative ion photoelectron (NIPE) spectrum with three partially resolved bands in the electron binding energy (eBE) range of 5.4 – 7.0 eV. These bands correspond to the transition from the ground state of the anion to the electronic ground state of [F-H-F]• neutral, with associated vibrational excitations. The significant increase of eBE of the bifluride anion, relative to that of F-, reflects a hydrogen bond energy between F- and HF of 46 kcal/mol. Theoretical modeling reveals that the antisymmetric motion of H between the two F atoms, near the TS on the neutral [F-H-F]• surface, dominates the observed three bands, while the F-H-F bending, F—F symmetric stretching modes, and the couplings between them is calculated to account for the breadth of the observed spectrum. From the NIPE spectrum, a lower limit on the activation enthalpy for F• + H-F F-H + F can be estimated to be H‡ = 12 ± 2 kcal/mol, a value below that of H‡ = 14.9 kcal/mol, given by our G4 calculations.},
doi = {10.1021/acs.jpca.7b07682},
journal = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},
number = 41,
volume = 121,
place = {United States},
year = {Thu Oct 05 00:00:00 EDT 2017},
month = {Thu Oct 05 00:00:00 EDT 2017}
}