ON THE USEFULNESS OF THE COUNTERPOISE METHOD ON HYDROGEN-BONDED COMPLEXES - A NUMERICAL TEST USING NEAR COMPLETE BASIS SETS ON H2O...HF, (H2O)(2), (HF)(2) AND CH4...H2O

摘要

Using the MP2 method and a wide range of basis sets which include up to near Hartree-Fock limit quality designed to saturate the s, p, d and f shells, we have evaluated the validity of the full counterpoise method (CP) as a way of correcting the basis set superposition errors (BSSE). We have selected for our tests the four hydrogen-bonded systems shown in the title in their minimum-energy conformation, to cover the 8-0.4 kcal/mol range of interaction energies. It is found for the four complexes that the CP method leads to a more accurate description of the interaction energies than the non-BSSE-corrected results, as long as the basis set employed has a minimum quality required for the description of the physical forces under consideration. The CP method gives interaction energies which are less dependent on the selected basis set than the uncorrected values and tend to an asymptote once a minimum quality is reached. [References: 37]