= Force-tilted activation barrier
{title2=$k(F)=k_0e^{F\Delta x/(k_BT)}$}
A constant tensile <force> changes a one-coordinate <free-energy landscape> from $G_0(x)$ to $G_0(x)-Fx$. To first order, an escape barrier decreases by $F\Delta x$, where $\Delta x$ is the saddle-to-initial-minimum displacement at zero <force>. An approximately fixed attempt prefactor gives the displayed rate law. Its characteristic <force> is $F_0=k_BT/\Delta x$. Large changes in saddle location or competing pathways invalidate a constant activation distance. The barrier is measured relative to the initial state; an absolute saddle <energy> is not enough to determine an escape rate.
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