DIPPED ADCLUSTER MODEL FOR CHEMISORPTIONS AND CATALYTIC REACTIONS ON A METAL-SURFACE - IMAGE FORCE CORRECTION AND APPLICATIONS TO PD-O2 ADCLUSTERS

Electrostatic term in the dipped adcluster model proposed previously is estimated by the method of image force. This is superior to the previous one which overestimates the electrostatic correction. The refined method is applied to the Pd-O2 adcluster dipped onto a free electron bath of the solid metal, the same system as reported previously. In addition to the highest spin coupling, the paired spin coupling is also applied. The former leads to a one-electron transfer and the latter a partial number (0.25) of electron transfer from a bulk metal into an adcluster. The geometry and the vibrational frequencies of the admolecule are not much affected by the electrostatic term, though the heat of adsorption is.