Figure 1.

Transitions among adjacent virtual states. Presuming that the system is at the filled‐circle position, where potential energy is $E_{\mathrm{R}}$ and the virtual state belongs to $v_i$, then, the virtual state might jump to $v_{i+1}$ without changing atomic positions (i.e., without changing $E_{\mathrm{R}}$). Its transition probability is given in eq. (7). However, when the system is at the open‐circle position, the virtual state might transition to $v_{i-1}$.