A COMPUTATIONAL STUDY OF THE STRUCTURES OF VAN-DER-WAALS AND HYDROGEN-BONDED COMPLEXES OF ETHENE AND ETHYNE - COMMENT

The weakly bonded complexes C2H2-Cl-2 and C2H2-HCl are studied using e xtended basis sets at the HF BLYP, B3LYP, and MP2 levels of theory. Th e interaction energies obtained from BLYP and B3LYP for the C2H2-Cl-2 and the C2H2-HCl are smaller than those from MP2 in our calculations. It is necessary that the extended basis set should be used in order to compare between the binding energies from various levels of theory fo r the investigation of weakly bonded complexes.