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Title: On the Ionization Energies of C4H3 Isomers

Abstract

We have conducted a combined experimental and theoretical study on the formation of distinct isomers of resonantly stabilized free radicals, C4H3, which are important intermediates in the formation of polycyclic aromatic hydrocarbons in combustion flames and possibly in the interstellar medium. Our study utilized laser ablation of graphite in combination with seeding the ablated species in neat methylacetylene gas which also acted as a reagent. Photoionization efficiency (PIE) curves were recorded of the C4H3 isomers at the Advanced Light Source from 8.0 to 10.3 eV. The experimental PIE curve was compared with theoretical ones suggesting the formation of four C4H3 radicals: two acyclic structures i-C4H3 [1] and E/Z-n-C4H3 [2E/2Z]and two cyclic isomers 3 and 4. These molecules are likely formed via an initial addition of ground state carbon atoms to the carbon-carbon triple bond of the methylacetylene molecule followed by isomerization via hydrogen migrations and ring opening and emission of atomic hydrogen from these intermediates.

Authors:
; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Chemical Sciences Division
OSTI Identifier:
973943
Report Number(s):
LBNL-2652E
Journal ID: ISSN 1439-4235; CPCHFT; TRN: US1002237
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
ChemPhysChem
Additional Journal Information:
Journal Name: ChemPhysChem; Journal ID: ISSN 1439-4235
Country of Publication:
United States
Language:
English
Subject:
99; 37; ABLATION; ADVANCED LIGHT SOURCE; ATOMS; CARBON; COMBUSTION; EFFICIENCY; FLAMES; GRAPHITE; GROUND STATES; HYDROGEN; IONIZATION; ISOMERIZATION; ISOMERS; LASERS; OPENINGS; PHOTOIONIZATION; POLYCYCLIC AROMATIC HYDROCARBONS; PROPYNE; RADICALS; Ionization, Energies, C4H3, Isomers

Citation Formats

Kaiser, Ralf I, Mebel, Alexander, Kostko, Oleg, and Ahmed, Musahid. On the Ionization Energies of C4H3 Isomers. United States: N. p., 2009. Web.
Kaiser, Ralf I, Mebel, Alexander, Kostko, Oleg, & Ahmed, Musahid. On the Ionization Energies of C4H3 Isomers. United States.
Kaiser, Ralf I, Mebel, Alexander, Kostko, Oleg, and Ahmed, Musahid. 2009. "On the Ionization Energies of C4H3 Isomers". United States. https://www.osti.gov/servlets/purl/973943.
@article{osti_973943,
title = {On the Ionization Energies of C4H3 Isomers},
author = {Kaiser, Ralf I and Mebel, Alexander and Kostko, Oleg and Ahmed, Musahid},
abstractNote = {We have conducted a combined experimental and theoretical study on the formation of distinct isomers of resonantly stabilized free radicals, C4H3, which are important intermediates in the formation of polycyclic aromatic hydrocarbons in combustion flames and possibly in the interstellar medium. Our study utilized laser ablation of graphite in combination with seeding the ablated species in neat methylacetylene gas which also acted as a reagent. Photoionization efficiency (PIE) curves were recorded of the C4H3 isomers at the Advanced Light Source from 8.0 to 10.3 eV. The experimental PIE curve was compared with theoretical ones suggesting the formation of four C4H3 radicals: two acyclic structures i-C4H3 [1] and E/Z-n-C4H3 [2E/2Z]and two cyclic isomers 3 and 4. These molecules are likely formed via an initial addition of ground state carbon atoms to the carbon-carbon triple bond of the methylacetylene molecule followed by isomerization via hydrogen migrations and ring opening and emission of atomic hydrogen from these intermediates.},
doi = {},
url = {https://www.osti.gov/biblio/973943}, journal = {ChemPhysChem},
issn = {1439-4235},
number = ,
volume = ,
place = {United States},
year = {Wed Sep 16 00:00:00 EDT 2009},
month = {Wed Sep 16 00:00:00 EDT 2009}
}