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On the time dependence of rate coefficients of irreversible reactions between reactants with anisotropic reactivity in liquid solutions.

Authors :
Ivanov, Konstantin L.
Lukzen, Nikita N.
Doktorov, Alexander B.
Source :
Journal of Chemical Physics. 2016, Vol. 145 Issue 6, p1-11. 11p. 2 Diagrams, 5 Graphs.
Publication Year :
2016

Abstract

Time dependence of the rate coefficients of sterically specific reactions is analyzed theoretically. Generally, such reactions exhibit a non-trivial dependence of their rate constant on the steric factor, ƒ < 1, which is defined as the fraction of reactive surface area. Notably, the rate constant of a diffusion-controlled reaction is proportional not to ƒ but, counter-intuitively, to√ƒ due to partial averaging of the reaction anisotropy by translational diffusion. Here we demonstrate that the effective steric factor of a diffusion-influenced reaction is strongly time-dependent, increasing from f to √ƒ. When reactants have several active sites, these sites "interfere" each other in the sense that the rate constant depends on their relative positions. We demonstrate that such an interference effect is strongly time-dependent as well: it is absent at t = 0 but builds up with time. We argue that the outlined effects are also of importance for calculating the fluorescence quenching rate constants. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219606
Volume :
145
Issue :
6
Database :
Academic Search Index
Journal :
Journal of Chemical Physics
Publication Type :
Academic Journal
Accession number :
117540356
Full Text :
https://doi.org/10.1063/1.4960174