Unimolecular reactions in isolated and collisional systems: Deuterium isotope effect in the photoisomerization of stilbene

Article abstract of DOI:10.1063/1.455342

The isomerization of t-stilbene (stilbene h₁₂ ) and three deuterated derivatives has been studied in a supersonic expansion, the thermal gas phase, and solution.In the jet we find that almost all effect of full deuteration (stilbene d₁₂ ) is produced by deuteration of the two ethylinic hydrogens only (stilbene d₂ ).Complete deuteration of the phenyl rings (stilbene dlo ) has rather little influence on the decay of the jet-cooled molecule.Nonexponential decays are found at intermediate excess energies in the jet-cooled system, with the degree of nonexponentiality decreasing with increasing excess energy.The ordering of the decay rates observed in the jet is not consistent with previous RRKM calculations of the isomerization rates of stilbene h₁₂ and d₂.Using similar parameters the calculations consistently place the stilbene d₂ and stilbene dlo curves in the wrong order.Our results suggest extensive but not complete vibrational relaxation in the isolated molecule.Vibrational redistribution rapidly becomes complete in the presence of buffer gas.In thermal samples the isomerization rates of stilbene h₁₂ and stilbene d₁₀ are identical over a wide range of solvents and temperatures.By contrast the isomerization rates in stilbene d₂ and stilbene d₁₂ are 1.4 and 1.5 times slower than in stilbene h₁₂ Again, these ratios appear constant over a wide range of experimental conditions.

Full text of DOI:10.1063/1.455342

Unimolecular reactions in isolated and collisional systems: Deuterium isotope effect
in the photoisomerization of stilbene
Scott H. Courtney, Michael W. Balk, Laura A. Philips, Steven P. Webb, Ding Yang, Donald H. Levy, and
Graham R. Fleming
Citation: The Journal of Chemical Physics 89, 6697 (1988); doi: 10.1063/1.455342
View online: http://dx.doi.org/10.1063/1.455342
View Table of Contents: http://scitation.aip.org/content/aip/journal/jcp/89/11?ver=pdfcov
Published by the AIP Publishing
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This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
130.113.111.210 On: Fri, 19 Dec 2014 06:33:15

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
130.113.111.210 On: Fri, 19 Dec 2014 06:33:15

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
130.113.111.210 On: Fri, 19 Dec 2014 06:33:15

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
130.113.111.210 On: Fri, 19 Dec 2014 06:33:15

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
130.113.111.210 On: Fri, 19 Dec 2014 06:33:15

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
130.113.111.210 On: Fri, 19 Dec 2014 06:33:15

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
130.113.111.210 On: Fri, 19 Dec 2014 06:33:15

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
130.113.111.210 On: Fri, 19 Dec 2014 06:33:15

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
130.113.111.210 On: Fri, 19 Dec 2014 06:33:15

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
130.113.111.210 On: Fri, 19 Dec 2014 06:33:15