Search

The interaction of manganese oxide clusters Mn x O y + ( x = 2-5, y ≥ x ) with CO 2 is studied via infrared multiple-photon dissociation spectroscopy (IR-MPD) in the spectral region of 630-1860 cm -1 . Along with vibrational modes of the manganese oxide cluster core, two bands are observed around 1200-1450 cm -1 and they are assigned to the characteristic Fermi resonance of CO 2 arising from anharmonic coupling between the symmetric stretch vibration and the overtone of the bending mode. The spectral position of the lower frequency band depends on the cluster size and the number of adsorbed CO 2 molecules, whereas the higher frequency band is largely unaffected. Despite these effects, the observation of the Fermi dyad indicates only a small perturbation of the CO 2 molecule. This finding is confirmed by the theoretical investigation of Mn 2 O 2 (CO 2 ) + revealing only small orbital mixing between the dimanganese oxide cluster and CO 2 , indicative of mainly electrostatic interaction.