On the curvature in logarithmic plots of rate coefficients for chemical reactions
<p>Abstract</p> <p>In terms of the reduced potential energy barrier ζ = Δ<it>u</it><sub><it>TS</it></sub>/<it>kT</it>, the rate coefficients for chemical reactions are usually expressed as proportional to <it>e</it><sup...
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doaj-64998a255504449da3a8a65371f4ccc62021-08-02T01:54:18ZengBMCChemistry Central Journal1752-153X2011-05-01512210.1186/1752-153X-5-22On the curvature in logarithmic plots of rate coefficients for chemical reactionsCanepa Carlo<p>Abstract</p> <p>In terms of the reduced potential energy barrier ζ = Δ<it>u</it><sub><it>TS</it></sub>/<it>kT</it>, the rate coefficients for chemical reactions are usually expressed as proportional to <it>e</it><sup>-<it>ζ</it></sup>. The coupling between vibrational modes of the medium to the reaction coordinate leads to a proportionality of the regularized gamma function of Euler <it>Q</it>(<it>a</it>,<it>ζ</it>) = Γ(<it>a</it>,<it>ζ</it>)/Γ(<it>a</it>), with <it>a </it>being the number of modes coupled to the reaction coordinate. In this work, the experimental rate coefficients at various temperatures for several chemical reactions were fitted to the theoretical expression in terms of <it>Q</it>(<it>a,ζ</it>) to determine the extent of its validity and generality. The new expression affords lower deviations from the experimental points in 29 cases out of 38 and it accounts for the curvature in the logarithmic plots of rate coefficients versus inverse temperature. In the absence of tunneling, conventional theories predict the curvature of these plots to be identically zero.</p> http://journal.chemistrycentral.com/content/5/1/22 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Canepa Carlo |
spellingShingle |
Canepa Carlo On the curvature in logarithmic plots of rate coefficients for chemical reactions Chemistry Central Journal |
author_facet |
Canepa Carlo |
author_sort |
Canepa Carlo |
title |
On the curvature in logarithmic plots of rate coefficients for chemical reactions |
title_short |
On the curvature in logarithmic plots of rate coefficients for chemical reactions |
title_full |
On the curvature in logarithmic plots of rate coefficients for chemical reactions |
title_fullStr |
On the curvature in logarithmic plots of rate coefficients for chemical reactions |
title_full_unstemmed |
On the curvature in logarithmic plots of rate coefficients for chemical reactions |
title_sort |
on the curvature in logarithmic plots of rate coefficients for chemical reactions |
publisher |
BMC |
series |
Chemistry Central Journal |
issn |
1752-153X |
publishDate |
2011-05-01 |
description |
<p>Abstract</p> <p>In terms of the reduced potential energy barrier ζ = Δ<it>u</it><sub><it>TS</it></sub>/<it>kT</it>, the rate coefficients for chemical reactions are usually expressed as proportional to <it>e</it><sup>-<it>ζ</it></sup>. The coupling between vibrational modes of the medium to the reaction coordinate leads to a proportionality of the regularized gamma function of Euler <it>Q</it>(<it>a</it>,<it>ζ</it>) = Γ(<it>a</it>,<it>ζ</it>)/Γ(<it>a</it>), with <it>a </it>being the number of modes coupled to the reaction coordinate. In this work, the experimental rate coefficients at various temperatures for several chemical reactions were fitted to the theoretical expression in terms of <it>Q</it>(<it>a,ζ</it>) to determine the extent of its validity and generality. The new expression affords lower deviations from the experimental points in 29 cases out of 38 and it accounts for the curvature in the logarithmic plots of rate coefficients versus inverse temperature. In the absence of tunneling, conventional theories predict the curvature of these plots to be identically zero.</p> |
url |
http://journal.chemistrycentral.com/content/5/1/22 |
work_keys_str_mv |
AT canepacarlo onthecurvatureinlogarithmicplotsofratecoefficientsforchemicalreactions |
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1721244277600681984 |