Solved and Unsolved Cases of Transition Metal Cluster Surface Morphologies and Activities*

We are investigating the surface morphology and adsorbate bonding properties of naked transition metal clusters under cryo conditions, and we have conducted a series of spectroscopic, kinetic and computational studies of the N₂ adsorption onto size selected Cobalt and Nickel clusters [1-4], as well as a case study of N₂ and H₂ co-adsorption onto a selected Ruthenium cluster [5]. In the course of these studies we chose to investigate Iron clusters and Iron-Rhodium nanoalloys as well. We found some Iron clusters reluctant to attach neither Nitrogen N₂ nor Hydrogen H₂. This presentation puts the current level of understanding to the stage.

[1] S. Dillinger, J. Mohrbach, J. Hewer, M. Gaffga, and G. Niedner-Schatteburg, Infrared spectroscopy of N₂ adsorption on size selected cobalt cluster cations in isolation, PCCP 17 (2015) 10358.
[2] J. Mohrbach, S. Dillinger, and G. Niedner-Schatteburg, Cryo Kinetics and Spectroscopy of Cationic Nickel Clusters: Rough and Smooth Surfaces, J. Phys. Chem. C 121 (2017) 10907.
[3] J. Mohrbach, S. Dillinger, and G. Niedner-Schatteburg, Probing cluster surface morphology by cryo kinetics of N₂ on cationic nickel clusters, J. Chem. Phys. 147, 184304 (2017) 184304.
[4] S. Dillinger, J. Mohrbach, and G. Niedner-Schatteburg, Probing cluster surface morphology by cryo spectroscopy of N₂ on cationic nickel clusters, J. Chem. Phys. 147, 184305 (2017) 184305.
[5] S. Dillinger, M. P. Klein, A. Steiner, D. C. McDonald, M. A. Duncan, M. M. Kappes, and G. Niedner-Schatteburg, Cryo IR Spectroscopy of N₂ and H₂ on Ru₈⁺: The Effect of N₂ on the H-Migration, J. Phys. Chem. Lett. 9 (2018) 914.