Production of large metallocarbohedrene clusters using a pulsed arc cluster ion source
Fachbereich für Physik, Universität Konstanz, 78457 Konstanz, Germany
Corresponding author: a firstname.lastname@example.org
Revised: 18 May 2001
Published online: 15 October 2001
The hypothesis of the existence of multi-cage structures of metallocarbohedrene clusters ("metcars" ) bases on the observation of certain magic numbers in the mass spectra corresponding to an excess of carbon atoms with respect to the bulk stochiometry (1:1 for TiC). E.g., the appearance of the magic number cluster Ti13C22 has been explained by assuming a double-cage structure. However, the same magic number can be assigned to a cube (= Ti13C14) with 8 additional carbon atoms forming carbon dimers at the corners of the cube. We recorded mass spectra of TinCm clusters using a pulsed arc cluster ion source with an additional annealing discharge. For the positive ions, Ti8C is the major peak in the mass spectrum. For the anions, much larger clusters could be generated. The maxima of the larger TinC clusters including Ti13C are located at masses slightly above the fcc cubic shell closings. The shift can be explained by the bonding of additional C atoms at the corners of the cubes.
PACS: 36.40.Mr – Spectroscopy and geometrical structure of clusters / 36.40.Wa – Charged clusters
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2001