Theoretical Investigation for the Molecular Structure and Binding Energies of C6H6+-(H2O)n (n = 1 - 5) Complexes

The geometrical parameters and binding energies of the benzene ion-water complex [C6H6 +-(H2O)(n) (n = 1 -5)] have been investigated using ab initio (MP2) and density functional theory (DFT) with large basis sets. The harmonic vibrational frequencies and IR intensities are also determined to confirm that all the optimized geometries are true minima. Also zero-point vibrational energies have been considered to predict the binding energies. The predicted binding energy of 8.6 kcal/mol for C6H6+-H2O at the MP2/aug-cc-pVTZ level of theory is in excellent agreement with recent experimental result of 8.5 +/- 1 kcal/mol.