Infrared spectroscopy of N sub(2) adsorption on size selected cobalt cluster cations in isolation

We report IR active N sub(2) stretching frequencies in isolated and size selected cobalt cluster nitrogen adsorbate complexes, [Con(N sub(2)) sub(1)] super(+) as recorded by virtue of InfraRed Photon Dissociation (IRPD) spectroscopy. The observed frequencies of the [Con(N sub(2)) sub(1)] super(+) complexes (n= 8-17) are significantly redshifted (2180 to 2290 cm super(-1)) with respect to the IR inactive vibrations of free N sub(2) (2359 cm super(-1)). These bands are assigned to a mu sub(1) head-on type of coordination of the N sub(2) to the cobalt cluster surface, revealing remarkable cluster size dependent features to interpret.