Figure 3.

(a) Plot of the cubic function describing V_eff at x₁ = 0, the bottom of the well at u = 0, and the top of the energy barrier of height Δ at u = u₀. (Dashed lines) Increasing applied force F, labeled on plot. (b) Contour plot of V_eff(x₁,u). (Darker areas) Lower energy values. In this plot we have chosen the values of $\tilde{\kappa }=\kappa u_0^2/\text{Δ}=0.4$ and $\tilde{f}=F{u}_0/\text{Δ}=0.3$. The latter value corresponds to the 0.2 of the critical force F_C. (Solid arrows) Approximation used to the preferred path O→A→C →B along the potential surface; (dashed line) example of another path, with lower potential barrier but an effectively much lower rate. To see this figure in color, go online.