On the effects of basis-set in studying the hydration and dissociation of HF in cubic HF(H2O)7 clusters

We have carried out a systematic study on the performance of Pople-style basis functions on the structure, electronic energies, vibrational spectra of the cubic HF(H2O)7 clusters with B3LYP method. Molecular structure and relative energy among the orientational isomers converge quickly with respect to the basis set and we found that, for most of the purposes, 6-311+G(d,p) represents the most economic choice to yield reliable results. Studies on the potential energy surface for the HF dissociation reactions show that smaller basis set tends to favor fluoric acid dissociation and the barrier height is sensitive to the basis set.