Figure 4. Enthalpy, entropy and derived conservative and entropic forces derived from the data in Figure 2b–g.

(a) Map of the enthalpy change ΔH^‡ obtained by fitting the rate maps from Fig. 3a with the logarithmic form of equation (1) using equation (5) for the (weakly) temperature dependent attempt rate, and ΔH^‡(x, y)≡E(x, y). (b) Corresponding error. (c) Entropy difference ΔS^‡ from the fit of (a). The right hand scale bar is a scale of the corresponding thermodynamic potential at T_iso, which can be compared with (a). (d) Corresponding error. (e) Conservative force, derived from (a). (f) Entropic force at T_iso, derived from (c). (g) Sum of conservative and entropic forces at T_iso, from (e,f). (h) Schematic of the free energy change along the transition axis, indicating the sign convention for the conservative, F_c, and entropic, F_e, forces on the molecule. All errors in the figure are s.d. Scale bars in (a–g), 1 nm.