The Lindemann type model

These general aspects are due originally to Lindemann [1], who first pointed out that a finite time is required for the decomposition of energised molecules. 

The simplest scheme neglects any energy dependence of the microscopic rate coefficients, viz. 

Considering the concentration of X at the steady state, the differential rate equation is obtained. 

X is then in equilibrium with X and the ratio k1/k2 is the fraction of molecules with energy above the critical threshold. The simple expression 

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