Binding energies of nitrile-containing proton-bound clusters: the performance of HF, MP2 and B3-LYP vs. G2

This study assesses a variety of computational methods for calculating the binding energies of proton-bound clusters containing a nitrile. The binding energies of (HCN)(2)H+, (HCN)(NH3)H+, (HCN)(H2O)H+ and (HCN)(HF)H+ were ca lculated at the HF, MP2 and B2-LYP levels of theory with a variety of basis sets, and the results compared to previous work; employing G2 based method s. Reliable binding energies could be obtained using the MP2/6-31 + G(d) an d B3-LYP/6-31 + G(d) levels of theory. The results were extended to a total of thirteen proton-bound dimers for which G2 values are available, and fou r multiply hydrated clusters (HCN)(H2O)(2)H+, (HCN)(H2O)(3)H+, (CH3CN)(H2O) (2)H+ and (CH3CN)(H2O)(3)H+. (C) 1999 Elsevier Science B.V. All rights rese rved.