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Vibrationally mediated photodissociation of ethene isotopic variants preexcited to the fourth C–H stretch overtone.

Vibrationally mediated photodissociation of ethene isotopic variants preexcited to the fourth C–H stretch overtone.

Authors :
Bespechansky, Evgeny
Portnov, Alexander
Zwielly, Amir
Rosenwaks, Salman
Bar, Ilana
Source :
Journal of Chemical Physics; 10/7/2006, Vol. 125 Issue 13, p133301, 8p, 2 Charts, 4 Graphs
Publication Year :
2006

Abstract

H and D photofragments produced via vibrationally mediated photodissociation of jet-cooled normal ethene (C<subscript>2</subscript>H<subscript>4</subscript>), 1,2-trans-d<subscript>2</subscript>-ethene (HDCCDH), and 1,1-d<subscript>2</subscript>-ethene (CH<subscript>2</subscript>CD<subscript>2</subscript>), initially excited to the fourth C–H stretch overtone region, were studied for the first time. H and D vibrational action spectra and Doppler profiles were measured. The action spectra include partially resolved features due to rotational cooling, while the monitored room temperature photoacoustic spectra exhibit only a very broad feature in each species. Simulation of the spectral contours allowed determination of the band types and origins, limited precision rotational constants, and linewidths, providing time scales for energy redistribution. The H and D Doppler profiles correspond to low average translational energies and show slight preferential C–H over C–D bond cleavage in the deuterated variants. The propensities toward H photofragments emerge even though the energy flow out of the initially prepared C–H stretch is on a picosecond time scale and the photodissociation occurs following internal conversion, indicating a more effective release of the light H atoms. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219606
Volume :
125
Issue :
13
Database :
Complementary Index
Journal :
Journal of Chemical Physics
Publication Type :
Academic Journal
Accession number :
22673577
Full Text :
https://doi.org/10.1063/1.2217743