Heidelberg 2015 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 25: Clusters in Molecular Physics (with MO & MS)

A 25.2: Vortrag

Mittwoch, 25. März 2015, 15:00–15:15, PH/SR106

Vibrational spectra and structures of C, B, and N-doped silicon clusters — •Nguyen Xuan Truong, Bertram Jaeger, Philip Jäger, Marco Savoca, Andre Fielicke, and Otto Dopfer — IOAP, TU-Berlin, Germany

Doping Si clusters changes their physical and chemical properties in a way that might be promising for the miniaturization trend towards nanoelectronics. Here, we investigated Si clusters doped with C, B and N with resonant infrared-ultraviolet two-color ionization (IR-UV2CI) and global optimization coupled with electronic structure methods. Doped Si clusters are irradiated with tunable IR light from a Free Electron Laser before being ionized with UV photons from an F2 laser. Resonant absorption of IR photons leads to an enhanced ionization efficiency for the neutral clusters and provides the size-specific IR-UV2CI spectra. Structural assignment of the clusters is achieved by comparing the experimental IR-UV2CI spectrum with the calculated linear absorption spectra of the most stable isomers. Low-energy isomers are found with the help of genetic and basin-hopping algorithms. For SimCn (with m+n=6), we observed the systematic transition from chain like geometries for C6 to 3D structures for Si6. We showed for the first row doped Si6X (with X = Be, B, C, N, O) clusters that different structures, vibrational and electronic properties can be achieved depending on the nature of the dopant atom. All dopant atoms in Si6X have a negative net charge suggesting that Si atoms act as electron donors within the clusters. Finally, vibrational spectra and structural assignments for B and N-doped Si clusters are discussed in detail.

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