Two-step catalytic waiting time
= Two-step catalytic waiting time
{title2=$p(t)=\frac{k_ak_b}{k_a-k_b}(e^{-k_bt}-e^{-k_at})$}
The convolution of two independent sequential exponential waiting times has the displayed normalized <density> and mean $k_a^{-1}+k_b^{-1}$. At equal rates its limit is $k^2te^{-kt}$. A measured <density> of this form supports a multistep kinetic mechanism without uniquely identifying its hidden chemical intermediates.