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Title: Multiplexed photoionization mass spectrometry investigation of the O( 3P) + propyne reaction

Here, the reaction of O( 3P) + propyne (C 3H 4) was investigated at 298 K and 4 Torr using time-resolved multiplexed photoionization mass spectrometry and a synchrotron-generated tunable vacuum ultraviolet light source. The time-resolved mass spectra of the observed products suggest five major channels under our conditions: C 2H 3 + HCO, CH 3 + HCCO, H + CH 3CCO, C 2H 4 + CO, and C 2H 2 + H 2 + CO. The relative branching ratios for these channels were found to be 1.00, (0.35 ± 0.11), (0.18 ± 0.10), (0.73 ± 0.27), and (1.31 ± 0.62). In addition, we observed signals consistent with minor production of C 3H 3 + OH and H 2 + CH 2CCO, although we cannot conclusively assign them as direct product channels from O( 3P) + propyne. The direct abstraction mechanism plays only a minor role (≤1%), and we estimate that O( 3P) addition to the central carbon of propyne accounts for 10% of products, with addition to the terminal carbon accounting for the remaining 89%. The isotopologues observed in experiments using d1-propyne (CH 3CCD) and analysis of product branching in light of previously computed stationary points on the singlet andmore » triplet potential energy surfaces (PESs) relevant to O( 3P) + propyne suggest that, under our conditions, (84 ± 14)% of the observed product channels from O( 3P) + propyne result from intersystem crossing from the initial triplet PES to the lower-lying singlet PES.« less
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [1] ;  [1]
  1. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
  2. Univ. of the Pacific, Stockton, CA (United States)
Publication Date:
Report Number(s):
SAND-016-10079J
Journal ID: ISSN 1089-5639; 648114
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory
Additional Journal Information:
Journal Volume: 119; Journal Issue: 28; Journal ID: ISSN 1089-5639
Publisher:
American Chemical Society
Research Org:
Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1329621

Savee, John D., Borkar, Sampada, Welz, Oliver, Sztaray, Balint, Taatjes, Craig A., and Osborn, David L.. Multiplexed photoionization mass spectrometry investigation of the O(3P) + propyne reaction. United States: N. p., Web. doi:10.1021/acs.jpca.5b00491.
Savee, John D., Borkar, Sampada, Welz, Oliver, Sztaray, Balint, Taatjes, Craig A., & Osborn, David L.. Multiplexed photoionization mass spectrometry investigation of the O(3P) + propyne reaction. United States. doi:10.1021/acs.jpca.5b00491.
Savee, John D., Borkar, Sampada, Welz, Oliver, Sztaray, Balint, Taatjes, Craig A., and Osborn, David L.. 2015. "Multiplexed photoionization mass spectrometry investigation of the O(3P) + propyne reaction". United States. doi:10.1021/acs.jpca.5b00491. https://www.osti.gov/servlets/purl/1329621.
@article{osti_1329621,
title = {Multiplexed photoionization mass spectrometry investigation of the O(3P) + propyne reaction},
author = {Savee, John D. and Borkar, Sampada and Welz, Oliver and Sztaray, Balint and Taatjes, Craig A. and Osborn, David L.},
abstractNote = {Here, the reaction of O(3P) + propyne (C3H4) was investigated at 298 K and 4 Torr using time-resolved multiplexed photoionization mass spectrometry and a synchrotron-generated tunable vacuum ultraviolet light source. The time-resolved mass spectra of the observed products suggest five major channels under our conditions: C2H3 + HCO, CH3 + HCCO, H + CH3CCO, C2H4 + CO, and C2H2 + H2 + CO. The relative branching ratios for these channels were found to be 1.00, (0.35 ± 0.11), (0.18 ± 0.10), (0.73 ± 0.27), and (1.31 ± 0.62). In addition, we observed signals consistent with minor production of C3H3 + OH and H2 + CH2CCO, although we cannot conclusively assign them as direct product channels from O(3P) + propyne. The direct abstraction mechanism plays only a minor role (≤1%), and we estimate that O(3P) addition to the central carbon of propyne accounts for 10% of products, with addition to the terminal carbon accounting for the remaining 89%. The isotopologues observed in experiments using d1-propyne (CH3CCD) and analysis of product branching in light of previously computed stationary points on the singlet and triplet potential energy surfaces (PESs) relevant to O(3P) + propyne suggest that, under our conditions, (84 ± 14)% of the observed product channels from O(3P) + propyne result from intersystem crossing from the initial triplet PES to the lower-lying singlet PES.},
doi = {10.1021/acs.jpca.5b00491},
journal = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},
number = 28,
volume = 119,
place = {United States},
year = {2015},
month = {5}
}