Elektronische Struktur von dotierten Siliziumclustern und Metallcluster-Kohlenwasserstoff-Hybriden
Zusammenfassung der Projektergebnisse
Silicon clusters have been of large interest over many years due to the possible relevance of nanosized Si particles for electronic and optical applications and there have been already a lot of studies focusing on investigating their structural evolution. Doping the clusters with transition metal or other main group metals gives additional degrees of freedom and is expected to strongly influence structural, electronic, and optical properties. Within our studies we have focused on characterizing pure as well as a wide range of doped clusters using infrared spectroscopy. These experiments using intense and widely tunable infrared free electron lasers deliver cluster size and composition specific spectra for isolated clusters in the gas phase. For cationic clusters mostly the infrared photodissociation of weekly bound rare gas complexes has been used to obtain the IR spectra, while for neutral clusters we have developed an IR-UV two color ionization scheme. Based on the experimental spectra firm and detailed structural assignments are developed via comparison with predictions from density functional theory calculations. For the pure silicon clusters we identify structures based on bipyramidal motifs, a trigonal prism as central unit is found in larger clusters. Structures of neutral and cationic clusters are very similar, only for Si8 a major structural change is observed due to bond weakening by loss of an electron from the HOMO. For the transition metal doped clusters three different growth principles can be observed. Depending on the interaction between Si and metal, the dopant can simply add to a bare silicon cluster, it can substitute a silicon atom of a bare cluster or it can lead to a complete structural reconstruction producing entirely new geometries. A result of the later process is the formation of particularly stable metal doped cage structures.
Projektbezogene Publikationen (Auswahl)
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Gas-phase structures of neutral silicon clusters, J. Chem. Phys. 136, 064301, 2012
M. Haertelt, J.T. Lyon, P. Claes, J. de Haeck, P. Lievens, A. Fielicke
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Probing the structures of neutral boron clusters using infrared/vacuum ultraviolet two color ionization: B11, B16, and B17, J. Chem. Phys. 137, 014317, 2012
C. Romanescu, D.J. Harding, A. Fielicke, L. S. Wang
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Incipient chemical bond formation of Xe to a cationic silicon cluster: Vibrational spectroscopy and structure of the Si4Xe+ complex, Chem. Phys. Lett. 557, 49, 2013
M. Savoca, J. Langer, D.J. Harding, O. Dopfer, A. Fielicke
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Vibrational Spectra and Structures of Neutral SimCn Clusters (m + n = 6): Sequential Doping of Silicon Clusters with Carbon Atoms, J. Phys. Chem. A 117, 1158, 2013
M. Savoca, A. Lagutschenkov, J. Langer, D.J. Harding, A. Fielicke, O. Dopfer
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Vibrational spectra and structures of bare and Xe-tagged cationic SinOm+ clusters, J. Chem. Phys. 141, 104313, 2014
M. Savoca, J. Langer, D.J. Harding, D. Palagin, K. Reuter, O. Dopfer, A. Fielicke
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Vibrational spectra and structures of neutral Si6X clusters (X=Be, B, C, N, O), PCCP 16, 22364, 2014
N.X. Truong, M. Savoca, D.J. Harding, A. Fielicke, O. Dopfer
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Characterization of neutral boron-silicon clusters using infrared spectroscopy: The case of Si6B, Int. J. Mass Spectr. 395, 1, 2016
N. X. Truong, M. Haertelt, B. Jaeger, S. Gewinner, W. Schöllkopf, A. Fielicke, O. Dopfer
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Structural Determination of Niobium-Doped Silicon Clusters by Far-infrared Spectroscopy and Theory, PCCP 18, 6291, 2016
X. Li, P. Claes, M. Haertelt, P. Lievens, E. Janssens, A. Fielicke
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Infrared Spectroscopy and Structures of Boron-Doped Silicon Clusters (SinBm, n = 3–8, m = 1–2), J. Phys. Chem. C. 121, 9560, 2017
N. X. Truong, B. K. A. Jaeger, S. Gewinner, W. Schöllkopf, A. Fielicke, O. Dopfer
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Structure and Fluxionality of B13+ Probed by Infrared Photodissociation Spectroscopy, Angew. Chem. Int. Ed. 56, 501, 2017
M. R. Fagiani, X. Song, P. Petkov, S. Debnath, S. Gewinner, W. Schöllkopf, T. Heine, A. Fielicke, K. R. Asmis
