 Sliding diffusivity with per-step dissociation

For an unbiased one-dimensional walk with step size $a$, diffusion coefficient $D$ fixes step interval $a^2/(2D)$. A small dissociation probability $P$ per step gives about $1/P$ steps before release. Thus lifetime depends on $D$, while the root-mean-square net displacement before release is $a/\sqrt{P}$. Net displacement is not the cumulative distance along all backtracking steps. Physically impossible printed diffusivities should not be silently replaced by a guessed exponent.