Calibration of a computational scheme for solvation studies: halide ions bound to water X(H₂O)⁻ (X = F, Cl, Br)

Abstract

This study investigates the effect of basis set on the DFT-derived geometries and energies of halide ion-water complexes towards determining the optimum computational scheme for the study of larger clusters. It is shown that currently available methods are unable to adequately describe the anion-water clusters, mainly due to the residual BSSE even when the largest basis sets are used. This is also reflected in the fact that a basis-set converged geometry is not obtained even at the B3LYP/aug-cc-pV5Z level. There also appears to be a significant difference in geometry when counterpoise-corrected optimizations are performed at this level, suggesting that BSSE is the major contributor to the difficulties in modelling these systems.

Acknowledgements

The authors wish to thank the Natural Sciences and Engineering Research Council of Canada (NSERC) for financial support. BV would also like to thank the Walter C. Sumner Foundation for a graduate student fellowship.