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Title: Photodissociation dynamics of the singlet and triplet states of the NCN radical

Abstract

The spectroscopy and photodissociation dynamics of the NCN radical have been investigated by fast beam photofragment translational spectroscopy. The [tilde B] hthinsp;[sup 3][Sigma][sub u][sup [minus]][l arrow][tilde X] hthinsp;[sup 3][Sigma][sub g][sup [minus]], [tilde c] hthinsp;[sup 1][Pi][sub u][l arrow][tilde a] hthinsp;[sup 1][Delta][sub g], and [tilde d] hthinsp;[sup 1][Delta][sub u][l arrow][tilde a] hthinsp;[sup 1][Delta][sub g] transitions were examined. The major dissociation products for the [tilde B] hthinsp;[sup 3][Sigma][sub u][sup [minus]] and [tilde c] hthinsp;[sup 1][Pi][sub u] states are N[sub 2]([tilde X] hthinsp;[sup 1][Sigma][sub g][sup +])+C([sup 3]P), while the [tilde d] hthinsp;[sup 1][Delta][sub u] state dissociates to N[sub 2]([tilde X] hthinsp;[sup 1][Sigma][sub g][sup +])+C([sup 1]D). The dissociation channel, N([sup 4]S)+CN([tilde X] hthinsp;[sup 2][Sigma][sup +]) is observed for the [tilde B] hthinsp;[sup 3][Sigma][sub u][sup [minus]] state at photon energies greater than 4.9 eV, where it comprises [approx]25[plus minus]10[percent] of the total signal. At all photon energies, the photofragment translational energy distributions show a resolved progression corresponding to the vibrational excitation of the N[sub 2] photofragment. The rotational distributions of the molecular fragments suggest that the dissociation pathway for the N[sub 2] loss channel involves a bent transition state while the N+CN photofragments are produced via a linear dissociation mechanism. The P(E[sub T]) distributions provide bondmore » dissociation energies of 2.54[plus minus]0.030 and 4.56[plus minus]0.040 hthinsp;eV for the N[sub 2] and CN loss channels, respectively, yielding [Delta]H[sub f,0 K](NCN)=4.83[plus minus]0.030 eV. [copyright] [ital 1999 American Institute of Physics.]« less

Authors:
; ;  [1]
  1. (Department of Chemistry, University of California, Berkeley, California 94720 (United States) Chemical Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720 (United States))
Publication Date:
OSTI Identifier:
6173005
Alternate Identifier(s):
OSTI ID: 6173005
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 111:11; Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; COMBUSTION PRODUCTS; CYANOGEN; DISSOCIATION ENERGY; ELECTRONIC STRUCTURE; NITROGEN COMPOUNDS; PHOTOLYSIS; RADICALS; REACTION INTERMEDIATES; CHEMICAL REACTIONS; DECOMPOSITION; ENERGY; PHOTOCHEMICAL REACTIONS 400500* -- Photochemistry

Citation Formats

Bise, R.T., Choi, H., and Neumark, D.M. Photodissociation dynamics of the singlet and triplet states of the NCN radical. United States: N. p., 1999. Web. doi:10.1063/1.479751.
Bise, R.T., Choi, H., & Neumark, D.M. Photodissociation dynamics of the singlet and triplet states of the NCN radical. United States. doi:10.1063/1.479751.
Bise, R.T., Choi, H., and Neumark, D.M. Wed . "Photodissociation dynamics of the singlet and triplet states of the NCN radical". United States. doi:10.1063/1.479751.
@article{osti_6173005,
title = {Photodissociation dynamics of the singlet and triplet states of the NCN radical},
author = {Bise, R.T. and Choi, H. and Neumark, D.M.},
abstractNote = {The spectroscopy and photodissociation dynamics of the NCN radical have been investigated by fast beam photofragment translational spectroscopy. The [tilde B] hthinsp;[sup 3][Sigma][sub u][sup [minus]][l arrow][tilde X] hthinsp;[sup 3][Sigma][sub g][sup [minus]], [tilde c] hthinsp;[sup 1][Pi][sub u][l arrow][tilde a] hthinsp;[sup 1][Delta][sub g], and [tilde d] hthinsp;[sup 1][Delta][sub u][l arrow][tilde a] hthinsp;[sup 1][Delta][sub g] transitions were examined. The major dissociation products for the [tilde B] hthinsp;[sup 3][Sigma][sub u][sup [minus]] and [tilde c] hthinsp;[sup 1][Pi][sub u] states are N[sub 2]([tilde X] hthinsp;[sup 1][Sigma][sub g][sup +])+C([sup 3]P), while the [tilde d] hthinsp;[sup 1][Delta][sub u] state dissociates to N[sub 2]([tilde X] hthinsp;[sup 1][Sigma][sub g][sup +])+C([sup 1]D). The dissociation channel, N([sup 4]S)+CN([tilde X] hthinsp;[sup 2][Sigma][sup +]) is observed for the [tilde B] hthinsp;[sup 3][Sigma][sub u][sup [minus]] state at photon energies greater than 4.9 eV, where it comprises [approx]25[plus minus]10[percent] of the total signal. At all photon energies, the photofragment translational energy distributions show a resolved progression corresponding to the vibrational excitation of the N[sub 2] photofragment. The rotational distributions of the molecular fragments suggest that the dissociation pathway for the N[sub 2] loss channel involves a bent transition state while the N+CN photofragments are produced via a linear dissociation mechanism. The P(E[sub T]) distributions provide bond dissociation energies of 2.54[plus minus]0.030 and 4.56[plus minus]0.040 hthinsp;eV for the N[sub 2] and CN loss channels, respectively, yielding [Delta]H[sub f,0 K](NCN)=4.83[plus minus]0.030 eV. [copyright] [ital 1999 American Institute of Physics.]},
doi = {10.1063/1.479751},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = ,
volume = 111:11,
place = {United States},
year = {1999},
month = {9}
}