In a solvation process (for example Eqs. 9 and 8), -T S U,V is strictly positive (guaranteed by Jensen's inequality), which is due to the fact that the solute and solvent are uncorrelated when the solute is decoupled from the solvent (λ = 0), and transferring the solute from an ideal gas into a solvated state necessarily increases solute-solvent correlations (broadening the E U,V distribution), and therefore results in a repulsive decrease in the solute-solvent entropy. For example, the excluded volume effect associated with inserting the solute into the solvent (with λ > 0) correlates the solute and solvent positions since only one species can occupy a given volume at one time.