MBPT STUDY OF THE CO-H-2 VAN-DER-WAALS INTERACTION

The many-body perturbation theory (MBPT) is employed for the calculati on of the intermolecular interaction potential for the linear CO...H-2 dimer in the framework of the supermolecule approach, using the POL1 basis described recently by Sadlej. This basis set, designed to reprod uce electric properties of molecules accurately, leads to a correct ca lculation of the counterpoise-corrected interaction energies, in excel lent agreement with results obtained in the larger basis set used in t his study for comparison, and with the best theoretical values availab le to date. The minimum of the MBPT(4) interaction energy curves occur s at 8.14 and 8.03 a(0), with well depths of 9.16 and 10.66 meV for th e POL1 and larger basis set calculations, respectively. In agreement w ith very recent spectroscopic results, a vibrationally bonded ground s tate is also predicted for this linear dimer.