Ultraviolet Absorption Spectrum and Cross Sections of Vinyl [C2H3] Radical in the 225-238 nm Region

Published

September 15, 1998

Author(s)

Askar Fahr, P Hassanzadeh, D B. Atkinson

Abstract

The room temperature gas phase ultraviolet absorption spectrum and cross sections of vinyl [C₂H₃] radicals have been determined in the spectral range 225 nm-238 nm, employing cavity ring-down absorption spectroscopy. Vinyl radicals in these experiments were produced from the 193-nm excimer laser photolysis of methyl-vinyl-ketone [CH₃COC₂H₃] and vinyl bromide [C₂H₃Br]. The spectra obtained from the two systems were nearly identical. The observed spectrum exhibits a relatively broad and featureless absorption with a cross section of 5.3 x 10¹⁸ cm² molecule^-1 at 230 nm. The electronic transitions in the vinyl radical have been calculated by ab initio quantum chemical methods at the CIS, EOM-CCSD, CASSCF and CASPT2 levels of theories and assign the new observed band to the highly allowed and in plane π* [2a]

Citation

Journal of Physical Chemistry

Volume

236

Issue

1-3

Pub Type

Journals

Keywords

ab initio methods, cavity ring down spectroscopy, cross sections, electronic transitions, gas phase, ultraviolet absorption, Vinyl Radical

Citation

Fahr, A. , Hassanzadeh, P. and Atkinson, D. (1998), Ultraviolet Absorption Spectrum and Cross Sections of Vinyl [C₂H₃] Radical in the 225-238 nm Region, Journal of Physical Chemistry (Accessed October 3, 2025)