Suche
Anzeige der Dokumente 81-90 von 330
Dissertation
Theory of laser-induced ultrafast structural changes in solids
(2010-04-21)
The present thesis is a contribution to the study of laser-solid interaction.
Despite the numerous applications resulting from the recent use of laser technology, there is still a lack of satisfactory answers to theoretical questions regarding the mechanism leading to the structural changes induced by femtosecond lasers in materials.
We provide here theoretical approaches for the description of the structural response of different solids (cerium, samarium sulfide, bismuth and germanium) to femtosecond laser ...
Aufsatz
Autoionization and fragmentation of Na_2 studied by femtosecond laser pulses
(F. Ehlotzky (Ed.), 1989)
Aufsatz
Transitions between quintet states of doubly excited four-electron ions
(1990)
Following an earlier observation in F VI we identified the line pair 1s2s2p^2 {^5P}-1s2s2p3d {^5P^0}
, {^5D^0} for the elements N, O, Mg, and tentatively for A1 and Si in beam-foil spectra. Assignment was established by comparison with Multi-Configuration Dirac-Fock calculations along the isoelectronic sequence. Using this method we also identified some quartet lines of lithium-like ions with Z > 10.
Aufsatz
Equilibrium K-shell excitation of highly ionized neon
(1979)
Augerelectron emission from foil-excited Ne-ions (6 to 10 MeV beam energy) has been
measured. The beam-foil time-of-flight technique has been applied to study electronic transitions of metastable states (delayed spectra) and to determine their lifetimes. To achieve a line identification for the complex structure observed in the prompt spectrum, the spectrum is separated into its isoelectronic parts by an Augerelectron-ion coincidence correlating the emitted electrons and the emitting projectiles of well defined final ...
Aufsatz
Kinematic dipole model for the anisotropy of quasimolecular X-rays
(1978)
For the angular dependence of quasimolecular X-ray emission in heavy ion colliding systems we present a semiclassical adiabatic model taking into account spontaneous dipole radiation. Using the most characteristic levels from a DFS-correlation diagram we are able to explain the behaviour of the observed anisotropy.
Aufsatz
State dependent volume isotope shift analysis of the low lying states of Ba I and Ba II
(1983)
Relativistic multi-configuration Dirac-Fock wavefunctions, coupled to good angular momentum J, have been calculated for low lying states of Ba I and Ba II. The resulting electronic factors show good agreement with data derived from recent high-resolution laser spectroscopy experiments and results from a comparison of muonic and optical data.
Aufsatz
Threshold behaviour of L x-ray excitation in Xe - Ag collisions
(1978)
In the collision system Xe - Ag, the thresholds for excitation of quasimolecular L radiation and characteristic Ag L radiation have been found to lie at about 5 MeV and 1 MeV, respectively. These results are discussed on the basis of ab initio calculations of the screened interaction potential and the electron-correlation diagram.
Aufsatz
Non-relativistic and relativistic molecular calculations for the chalcogen hexafluorides: SF_6, SeF_6, TeF_6, PoF_6
(1980)
Non-relativistic Hartree-Fock-Slater and relativistic Dirac-Slater self-consistent orbital models are applied for the analysis of the electronic structure of the chalcogen hexafluorides: SF_6, SeF_6, TeF_6 and PoF_6. The molecular eigenfunctions and eigenvalues are generated using the discrete variational method (DVM) with numerical basis functions. The results obtained for SF_6 are compared with other ab initio calculations. Information about relativistic level shifts and spin-orbit splitting has been obtained by ...
Aufsatz
Interpretation of noncharacteristic M X-rays in heavy colliding systems by selfconsistent relativistic molecular calculations
(1976)
The result of the first calculation of a self-consistent relativistic many electron correlation diagram ever done (for the system Au - I) leads to a good agreement of the spectral shape and position of the observed noncharacteristic X-rays within the quasi adiabatic model.
Aufsatz
Note on the quasimolecular M radiation in very heavy collision systems
(1976)
The quasimolecular M radiation emitted in collisions between Xe ions of up to 6 MeV energy and solid targets of Ta, Au, Pb and Bi, as well as a gaseous target of Pb(CH_3)_4, has been studied. Using a realistic theoretical correlation diagram, a semiquantitative explanation of the observed peak structure is given.