Table 2. Computed Solution Free Energies for [Li(H₂O)₃ATP]³⁻+[Mg(H₂O)₆]²⁺ → [Mg(H₂O)₅ATP]²⁻+[Li(H₂O)₄]⁺ using Different Methods^a.

Basis Set	6-311 + G(d)	6-311++G(d)	6-311++G(d,p)	6-311++ G(2d,2p)	6-31 + G(3d,p)	6-311++G(3d,p)
# of functions	848	866	920	1149	1187	1270
M062X	−3.7	−3.6	−5.5	−6.4	−6.7	−6.9
B3LYP-D3	−2.6	−2.4	−4.2	−4.6	−5.0	−5.1

^aExperimental value of −3.5 kcal/mol is determined from the binding constants of ATP-Mg (9554 M⁻¹) and ATP-Li (25 M⁻¹) complexes from Wilson and Chin, 1991¹².