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Aufsatz
Photoionization of Kr near the 4s threshold: IV. Photoionization through the autoionization of doubly-excited states
(1994)
The photoionization cross sections for the production of the Kr II 4s state and Kr II satellite states were studied in the 4s ionization threshold region. The interference of direct photoionization and ionization through the autoionization decay of doubly-excited states was considered. In the calculations of doubly-excited state energies, performed by a configuration interaction technique, the 4p spin-orbit interaction and the (Kr II core)-(excited electron) Coulomb interaction were included. The theoretical cross ...
Aufsatz
Photoionization of Kr near 4s threshold: II. Intermediate-coupling theory
(1994)
The Kr 4s-electron photoionization cross section as a function of the exciting-photon energy in the range between 30 eV and 90 eV was calculated using the configuration interaction (CI) technique in intermediate coupling. In the calculations the 4p spin-orbital interaction and corrections due to higher orders of perturbation theory (the so-called Coulomb interaction correlational decrease) were considered. Energies of Kr II states were calculated and agree with spectroscopic data within less than 10 meV. For some of ...
Aufsatz
Relativistic prediction of the ground state of atomic Lawrencium
(1980)
In contradiction to the prediction of the Periodic Table but in agreement with earlier suggestions by Brewer and Mann, the ground state configuration of atomic Lawrencium (Z = 103) will not be 7s^2 6d^2 D_3/2 but 7s^2 7p ^2p_1/2. The reason for this deviation from normal trends across the Periodic Table are strong relativistic effects on the outermost 7P_l/2 orbital. Multicontiguration Dirac-Fock calculations are reported for Lawrencium and analogous lighter atoms. These calculations include contributions from magnetic ...
Aufsatz
Two-muonic atoms
(1974)
X-ray transition energies for two-muonic atoms are calculated. The basis are relativistic self-consistent-field calculations including the corrections normally known in muonic atoms plus the vacuum polarization, magnetic interaction and retardation in the \mu-\mu-interaction, the specific mass correction and the configuration interaction.
Dissertation
The Surface Plasmon Resonance of Supported Noble Metal Nanoparticles: Characterization, Laser Tailoring, and SERS Application
(2007-07-20)
This work deals with the optical properties of supported noble metal nanoparticles, which are dominated by the so-called Mie resonance and are strongly dependent on the particles’ morphology. For this reason, characterization and control of the dimension of these systems are desired in order to optimize their applications. Gold and silver nanoparticles have been produced on dielectric supports like quartz glass, sapphire and rutile, by the technique of vapor deposition under ultra-high vacuum conditions. During the ...
Dissertation
Goldnanoteilchen auf Titandioxid
(2009-02-23)
In dieser Arbeit wurde das Wachstum sowie die ultraschnelle Elektronendynamik des Oberflächenplasmon Polaritons von Goldnanoteilchen auf Titandioxid untersucht. Die Messung der Dephasierungszeit des Oberflächenplasmons von Nanoteilchen mit definierter Form und Größe erfolgte dabei mit der Methode des spektralen Lochbrennens. Die Nanoteilchen wurden durch Deposition von Goldatomen aus einem thermischen Atomstrahl mit anschließender Diffussion und Nukleation, d.h. Volmer-Weber-Wachstum, auf Titandioxidsubstraten ...
Aufsatz
First results of experimental and theoretical investigations on sextet states of doubly-excited five-electron ions
(1992)
In continuation of our previous work on doubly-excited ions with three and four electrons we present the first results on optical transitions in the term system of doubly-excited ions with five electrons. Transitions between such sextet states were identified in beam-foil spectra of the ions nitrogen, oxygen and fluorine. Assignments were first established by comparison with Multi-Configuration Dirac-Fock calculations. Later assignments were aided by Multi-Configuration Hartree-Fock calculations (see the contribution ...
Aufsatz
Further investigations on doubly excited four-electron ions: beam-foil experiment and MCDF theory
(1991)
In continuation of our previous work on the quintet transitions 1s2s2p^2 ^5 P-1s2s2p3d ^5 P^0, ^5 D^0, results on other n = 2 - n' = 3 quintet transitions for elements N, 0 and F are presented. Assignments have been established by comparison with Multi-Configuration Dirac-Fock calculations. High spectral resolution on beam-foil spectroscopy was essential for the identification of most of the lines. For some of the quintet lines decay curves were measured, and the lifetimes extracted were found to be in reasonable ...
Aufsatz
Study of 3d - 4f and 3d - 5f quartet and doublet transitions of doubly excited three-electron ions
(1989)
We present the first observation of optical transitions between doubly excited doublet states in the term systems N V, 0 VI and F VII. The spectra were produced by foil excitation of fast ion beams. The assignment of the spectral lines was made by comparison with the results of MCDP calculations along the isoelectronic sequence. The same method also led to the identification of two 3d - 4f quartet transitions in Mg X.
Dissertation
Molecular Beam Epitaxial Growth of III-V Semiconductor Nanostructures on Silicon Substrates
(2013-07-24)
The main focus and concerns of this PhD thesis is the growth of III-V semiconductor nanostructures (Quantum dots (QDs) and quantum dashes) on silicon substrates using molecular beam epitaxy (MBE) technique. The investigation of influence of the major growth parameters on their basic properties (density, geometry, composition, size etc.) and the systematic haracterization of their structural and optical properties are the core of the research work. The monolithic integration of III-V optoelectronic devices with silicon ...