P Piseri et al 2006 New J. Phys. 8 136 doi:10.1088/1367-2630/8/8/136
P Piseri1,2, T Mazza1,2, G Bongiorno1,2, C Lenardi1,3, L Ravagnan1,2, F Della Foglia2, F DiFonzo2, M Coreno4,5,6, M DeSimone5,6, K C Prince6,7 and P Milani1,2,8
Show affiliationsSynchrotron radiation x-ray absorption spectroscopy (XAS) is one of the most powerful techniques to interrogate the local electronic structure and chemical status of bulk and nanostructured systems. The application of this technique to the study of size effects in free clusters of transition metal atoms would advance substantially fundamental knowledge of nano-objects and the tailoring of their magnetic and catalytic properties. To date core level spectroscopy of free transition metal clusters has been out of reach due to the lack of a cluster source able to produce clusters in the gas phase with a density suitable for synchrotron radiation sources. Here we demonstrate the XAS characterization of free titanium clusters in a supersonic molecular beam. We use a high-intensity cluster beam source coupled to a synchrotron beamline to investigate the size dependence of core level excitation of Tin clusters in the mass range 15<n<1000. The x-ray absorption of Tin evolves from a multi-peaked complex structure similar to that of Ti atoms towards spectra characterized by two main absorption features as in bulk titanium. The intensities and the fine structure of the spectra are size dependent showing regularities compatible with geometric shell closings and the presence of a structural transition at about 540 atoms/cluster.
41.60.Ap Synchrotron radiation
71.20.Be Transition metals and alloys
61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.
Accelerators, beams and electromagnetism
Issue 8 (August 2006)
Received 17 May 2006
Published 18 August 2006
P Piseri et al 2006 New J. Phys. 8 136
Liqun Yang et al 1994 Meas. Sci. Technol. 5 1096
Tomasz J Konopka and Seth A Major 2002 New J. Phys. 4 57
Stanislav N Gorb et al 2007 Bioinspir. Biomim. 2 S117
G Laplanche et al 1976 J. Phys. B: At. Mol. Phys. 9 1263
Asa K Rennermalm et al 2009 Environ. Res. Lett. 4 024011
H Schiefer et al 2009 Phys. Med. Biol. 54 4959
Derek Vollmer 2009 Environ. Res. Lett. 4 024003
Steven Q Andrews 2008 Environ. Res. Lett. 3 034009
Michael E Webber 2007 Environ. Res. Lett. 2 034007