Low temperature infrared spectra of CO adsorbed on the surface of MgO(0Â 0Â 1) thin films

Reflection-absorption infrared spectra of CO adsorbed on the surface of thin MgO(0 0 1) films are reported in the temperature range 30-90 K. The observed bands are identical with those reported earlier for MgO single crystals and powder samples. By selective population of low-coordinated (LC) sites and from the analysis of respective TPD spectra a desorption energy for LC sites of ∼25 kJ mol−1 was derived, in perfect agreement with recent findings on MgO powders. Experiments with 12CO/13CO give evidence for substantial infrared intensity transfer between neighboring CO oscillators and the formation of adsorbate complexes containing more than one CO molecule on low-coordinated sites.