Figure 1.

Root-mean-squared error (RMSE) in solvation free energy for different sets of molecules as a function of solvent internal pressure p and surface tension γ for a solute dielectric constant ɛ_m = 1.8 using the OPLS-AA force field.²⁹ (a) Linear, branched, and cyclic alkane set of Levy and Gallicchio;²⁷ (b) SAMPL0 set;²⁶ (c) SAMPL2 set;²⁸ (d) pooled set. The RMSE is normalized by RT = 0.592 kcal mol⁻¹ at 298 K, shown as contours. The linear regression fit of γ_min(p) vs. p is indicated in black, where γ_min(p) is the choice of γ at any given p which minimizes the RMSE (values provided in Table 1). The experimental values for the pressure¹⁰p = 0.0248 kcal mol⁻¹ Å⁻³ and surface tension¹¹ γ = 0.103 kcal mol⁻¹ Å⁻² are indicated with a cross on each plot and the minimum (γ, p) values are indicated with a circle.