Structure and binding energy of anion-π and cation-π complexes: A comparison of MP2, RI-MP2, DFT, and DF-DFT methods
D. Quiñonero, C. Garau, A. Frontera, P. Ballester, A. Costa, P. M. Deyà
J. Phys. Chem. A 2005, 109, 4632-4637
Abstract: Several complexes of benzene with cations, hexafluorobenzene with anions, 1,3,5-trifluorobenzene with cations and anions, and s-triazine with cations and anions have been evaluated and compared at the MP2 and resolution of the identity MP2 (RI-MP2) levels. The RI-MP2 method is considerably faster than the MP2 and the interaction energies and equilibrium distances are almost identical for both methods. A similar result is found when comparing DFT and density fitting DFT (DF-DFT) levels. Therefore RI-MP2 and DF-DFT methods are well suited for the study of ion−π interactions.