Table 4:

Summary of parameters used in transformations of illustrative 2-body model systems (taken from Joung and Cheatham ion monovalent parameters⁷⁸ and TIP3P water⁶²). The 1-body parameters (Q in units of ∣e∣, σ in units of Å, and ε in units of kcal/mol) for atoms are: Cs⁺ (Q=1.0, σ=1.888, ε=0.3944318); Li⁺ (Q=1.0, σ=0.808, ε=0.103984); Cl⁻ (Q=−1.0, σ = 2.760, ε=0.0116615); Na⁺ (Q=1.0, σ=1.226, ε=0.1684375); OW (Q=−0.834, σ=1.57535, ε=0.1521). The hydrophobic R group model was chosen as a LJ sphere of σ_ij=5.0 Å and ε_ij=1.0 kcal/mol, and Coulomb interaction between a OW atom and a R group charge Q=0.1∣e∣. For the annihilation models, and additional quadratic “surface tension” term of the form (1/2)k-r² was added (force constant k in units of kcal/mol·Å²) to capture the effect that a real solution would resist formation of an empty cavity. Particles were constrained to remain with a 10 Å range.

	λ=0 state				→	λ=1 state
Transformation	Qi·Qj	σij	εij	k		Qi·Qj	σij	εij	k
Na+ → 0	−0.834	2.80135	0.16006	1.0	→	-	-	-	1.0
Li+ → Cs+	−1.0	3.568	0.03482	-	→	−1.0	4.648	0.06782	-
R → 0	−0.0834	5.0	1.0	1.0	→	-	-	-	1.0