The effect of “full” and “limited” counterpoise corrections with different basis sets on the energy and the equilibrium distance of hydrogen bonded dimers

Abstract

AbstractA detailed analysis of the ΔE(R) curves for nine hydrogen bonded dimers involving HF, H2O, and NH3 as partners, computed with five basis sets (STO‐3G, MINI‐1, 3‐21G, 4‐31G, and 6‐31G**) and subjected to counterpoise (CP) corrections with three different methods is reported. Using several criteria and tests, the positive effect of full CP corrections for the description obtained with all the basis sets (with the exception of the STO‐3G one) is pointed out. The CP correction at the 6‐31G** levels is still sizable and improves the results with respect to the estimated Hartree–Fock limits of ΔE(Req) and Req. The results obtained with the application of the full CP correction to the MINI‐I energies are of relatively good quality. The STO‐3G energies at the SCF level are, on the contrary, overcorrected by the full CP correction and slightly improved by “limited” CP corrections: this basis set, however, is not recommended for calculations of geometries and stabilization energies of H‐bonded dimers of this size.