Erroneous behaviour of the widely used MP2(full)/aug-cc-pVXZ (X = D, T) level of theory for evaluating the BSSE in ion-pi complexes

Abstract

[eng] Several complexes of benzene with alkaline cations and s-triazine with halide anions have been optimized using the MP2 method and several double-f and triple-f basis sets. The BSSE (basis set superposition error) counterpoise correction on the ion-p complexes was computed for Pople's and Dunning's basis sets using both frozen core and full core MP2 methods. An anomalous behaviour of the widely used MP2(full)/aug-cc-pVXZ (X = D,T) level of theory was observed, specially for sodium complexes. It is solved using the MP2(full)/aug-cc-pCVXZ (X = D,T) level of theory