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Title: Identification and chemistry of C4H3 and C4H5 isomers in fuel-richflames

Abstract

No abstract prepared.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
COLLABORATION - SANDIA
OSTI Identifier:
929090
Report Number(s):
LBNL-59110
R&D Project: 403101; BnR: KC0301020; TRN: US200812%%601
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry A; Journal Volume: 110; Related Information: Journal Publication Date: 2006
Country of Publication:
United States
Language:
English
Subject:
37; CHEMISTRY; FLAMES; ISOMERS

Citation Formats

Hansen, N., Klippenstein, S.J., Taatjes, C.A., Miller, J.A., Wang, J., Cool, T.A., Yang, B., Yang, R., Wei, L., Huang, C., Wang, J., Qi, F., Law, M.E., and Westmoreland, P.R. Identification and chemistry of C4H3 and C4H5 isomers in fuel-richflames. United States: N. p., 2005. Web.
Hansen, N., Klippenstein, S.J., Taatjes, C.A., Miller, J.A., Wang, J., Cool, T.A., Yang, B., Yang, R., Wei, L., Huang, C., Wang, J., Qi, F., Law, M.E., & Westmoreland, P.R. Identification and chemistry of C4H3 and C4H5 isomers in fuel-richflames. United States.
Hansen, N., Klippenstein, S.J., Taatjes, C.A., Miller, J.A., Wang, J., Cool, T.A., Yang, B., Yang, R., Wei, L., Huang, C., Wang, J., Qi, F., Law, M.E., and Westmoreland, P.R. Mon . "Identification and chemistry of C4H3 and C4H5 isomers in fuel-richflames". United States. doi:.
@article{osti_929090,
title = {Identification and chemistry of C4H3 and C4H5 isomers in fuel-richflames},
author = {Hansen, N. and Klippenstein, S.J. and Taatjes, C.A. and Miller, J.A. and Wang, J. and Cool, T.A. and Yang, B. and Yang, R. and Wei, L. and Huang, C. and Wang, J. and Qi, F. and Law, M.E. and Westmoreland, P.R.},
abstractNote = {No abstract prepared.},
doi = {},
journal = {Journal of Physical Chemistry A},
number = ,
volume = 110,
place = {United States},
year = {Mon Nov 21 00:00:00 EST 2005},
month = {Mon Nov 21 00:00:00 EST 2005}
}
  • A new diffusion Monte Carlo study is performed on the isomers of C{sub 4}H{sub 3} and C{sub 4}H{sub 5} emulating the methodology of a previous study [Int. J. Chem. Kinetics 33, 808 (2001)]. Using the same trial wave function form of the previous study, substantially different isomerization energies were found owing to the use of larger walker populations in the present work. The energy differences between the E and I isomers of C{sub 4}H{sub 3} were found to be 10.5 {+-} 0.5 kcal/mol and for C{sub 4}H{sub 5}, 9.7 {+-} 0.6 kcal/mol. These results are in reasonable accord with recentmore » MRCI and CCSD(T) findings.« less
  • 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 C4H3more » 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.« less
  • In this article, we discuss in detail the addition of hydrogen atoms to diacetylene and the reverse dissociation reactions, H + C{sub 4}H{sub 2} {leftrightarrow} i-C{sub 4}H{sub 3} (R1) and H + C{sub 4}H{sub 2} n-C{sub 4}H{sub 3} (R2). The theory utilizes high-level electronic structure methodology to characterize the potential energy surface, Rice-Ramsperger-Kassel-Marcus (RRKM) theory to calculate microcanonical/J-resolved rate coefficients, and a two-dimensional master-equation approach to extract phenomenological (thermal) rate coefficients. Comparison is made with experimental results where they are available. The rate coefficients k{sub 1}(T, p) and k{sub 2}(T, p) are cast in forms that can be used inmore » chemical kinetic modeling. In addition, we predict values of the heats of formation of i-C{sub 4}H{sub 3} and n-C{sub 4}H{sub 3} and discuss their importance in flame chemistry. Our basis-set extrapolated, quadratic-configuration-interaction with single and double excitations (and triple excitations added perturbatively), QCISD(T), predictions of these heats of formation at 298 K are 130.8 kcal/mol for n-C{sub 4}H{sub 3} and 119.3 kcal/mol for the i-isomer; multireference CI calculations with a nine-electron, nine-orbital, complete-active-space (CAS) reference wavefunction give just slightly larger values for these parameters. Our results are in good agreement with the recent focal-point analysis of Wheeler et al. (J. Chem. Phys. 2004, 121, 8800-8813), but they differ substantially for {Delta} H{sub f 298}{sup 0}(n-C{sub 4}H{sub 3}) with the earlier diffusion Monte Carlo predictions of Krokidis et al.« less
  • No abstract prepared.
  • No abstract prepared.