abstracts - Институт катализа им. Г.К. Борескова

KS-III-4K on the same sites that account for ‘carbonite’ formation and for homomolecular isotopicscrambling of CO.Formation of catalysis intermediates often needs activation, and the corresponding IRbands cannot be seen, if adsorption occurs at too low temperature. Particularly interesting isthe case of thermal activation of states that arise reversibly with heating and could not bestabilized by freezing. Activated surface complexes could have the geometry different fromthose formed normally on the same sites. Such "steric excitation", where the energy is storedin non-optimum structure, was established for several types of adsorption, the most studied sofar is the case of CO in zeolites that besides the usual C-bonded complexes with the cations orOH-groups, forms energetically unfavorable O-bonded complexes.Quantitative analysis of surface adsorption sites is not possible without the knowledge ofabsorption coefficients of test molecules. Both quantum chemical calculations andelectrostatic approach predict the correlation between the frequency shifts on adsorption andthe absorption coefficients. Recent data on CO adsorption on ionic surfaces are in a fairagreement with the theory.61