Shane Flynn edited Kinetic model with dynamic disorder.tex  over 9 years ago

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To study the effect of dynamical disorder on higher-order kinetics, we adapt the Kohlrausch-Williams-Watts (KWW) model for stretched exponential decay. In first-order kinetics, stretched exponential decay involves a two-parameter survival function $\exp(-\omega t)^\beta$ and associated time-depedent rate coefficient, $k_{1,KWW}(t) = \beta(\omega t)^{\beta}/t$. The parameter $\omega$ is a characteristic rate or inverse time scale and the parameter $\beta$ is a measure of the degree of stretching. We showed in Reference~[citation] that stretching the exponential with $\beta$ increases the degree of dynamic disorder nonlinearly.  In general we can write the $n^{th}$ order rate law for the KWW model using the new formulations for the nonlinear differential KWW and survival functions. function.  \begin{equation}  \frac{d}{dt}[S(t)]=\frac{1}{n-1}(\frac{1}{1+z^\beta t^\beta})^{\frac{2-n}{n-1}}(\frac{-z^\beta\beta t^{\beta -1}}{(1+z^\beta t^\beta)^2})  \end{equation}