Clusters – in particular those of transition metals – may act like surfaces of limited size, this analogy being recognized long time ago . By virtue of our tandem cryo ion trap instrument we study the adsorption kinetics of clusters under single collision conditions as well as the Infrared Multiple Photon Dissociation (IR-MPD) by application of optical parametric oscillator/amplifier (OPO/OPA) photon sources . Also, one and two colour investigations of metal organic complexes by such technique were published .
Our ongoing studies of N2 and H2 cryo adsorption on Fe, Co, and Ni clusters and alike  revealed clearly discernible mono layer like adsorbate shells. Beyond such mere kinetics – though interesting in themselves – we recorded IR-MPD spectra of dinitrogen stretching vibrations within such [Mn(N2)m]+ cluster surface-adsorbate layer complexes by variation of their stoichiometry, n and of m alike, and in conjunction with electronic structure modelling (by DFT), and with synchrotron X-ray based studies of spin and orbital contributions to the total magnetic moments of the isolated clusters . Related studies of N2 coordination to ligand stabilized complexes provide for certain surprises .
This presentation shall elucidate the current state of cluster adsorbate studies under cryo conditions and in isolation. It aims to put into perspective the findings from adsorption kinetics, IR spectroscopy, DFT modelling and magnetic spectroscopy, much like a recent review article . The talk concludes with an outlook onto the road ahead.
This research originates from a long standing support by the DFG through the transregional collaborative research center SFB/TRR 88 3MET.de
 E. L. Muetterties et al., Chem. Rev., 1979, 79, 91-137; G. Ertl, Angew. Chem. Int. Ed., 2008, 47, 3524 – 3535.
 S. Dillinger et al., Phys. Chem. Chem. Phys. 2015, 17, 10358; J. Mohrbach et al., J.Phys.Chem. C 2016, in revision.
 Y. Nosenko et al., Phys. Chem. Chem. Phys. 2013, 15, 8171; J. Lang et al., Phys. Chem.Chem. Phys. 2014, 16, 17417 – 17421; M. Gaffga et al., J. Phys. Chem. 2015, 119, 12587; J. Lang et al., Chemistry 2016, 22, 2345.
 S. Peredkov et al., Phys. Rev. Lett. 2011, 107, 233401; J. Meyer et al., J. Chem. Phys. 2015, 143, 104302.
 J. Lang et al., Chem. Comm. 2016, in print, DOI: 10.1039/C6CC07481B.
 GNS, Struct. Bond. 2016, in print, DOI: 10.1007/430_2016_11