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Now showing items 11-20 of 74
Aufsatz
Inclusive probabilities for the scattering system 16 MeV-S{^16+} on Ar
(1991)
We performed ab initio calculations of many particle inclusive probabilities for the scattering system 16 MeV-S{^16+} on Ar. The solution of the time-dependent DIRAC-FOCK-SLATER-equation is achieved via a set of coupled-channel equations with energy eigenvalues and matrix elements which are given by static SCF molecular many
electron calculations.
Aufsatz
Solution of the time dependent Dirac-Fock-Slater equation for many-electron collisions systems using a time window method
(1994)
We present a new scheme to solve the time dependent Dirac-Fock-Slater equation (TDDFS) for heavy many electron ion-atom collision systems. Up to now time independent self consistent molecular orbitals have been used to expand the time dependent wavefunction and rather complicated potential coupling matrix elements have been neglected. Our idea is to
minimize the potential coupling by using the time dependent electronic density to generate molecular basis functions. We present the first results for 16 MeV S{^16+} on Ar.
Aufsatz
Femtosecond spectroscopy of molecular autoionization and fragmentation
(1990)
Femtosecond laser pulses are applied to the study of the dynamics and the pathways of multiphoton-induced ionization, autoionization, and fragmentation of Na_2 in molecular-beam experiments. In particular,
we report on first results obtained studying electronic autoionization (leading to Na_2{^+} + {e ^-}) and
autoionization-induced fragmentation (leading to Na{^+} + Na + {e ^-}) of a bound doubly excited molecular state. The final continuum states are analyzed by photoelectron spectroscopy and by measuring the ...
Aufsatz
Photoionization of Kr 4s: III. Detailed and extended measurements of the Kr 4s-electron ionization cross section
(1994)
Absolute Kr 4s-electron photoionization cross sections as a function of the exciting-photon energy were measured by photon-induced fluorescence spectroscopy (PIFS) at improved primary-energy resolution. The cross sections were determined from threshold to
33.5 eV and to 90 eV with primary-photon bandwidths of 25 meV and 50 meV, respectively. The measurements were compared with experimental data and selected theoretical calculations for the direct Kr 4s-electron photoionization cross sections.
Aufsatz
Double photoionization of argon into the {3s3p^5} {^1P}- and {^3P}-states
(1994)
Double photoionization of argon was studied
by photon induced fluorescence spectroscopy (PIFS). Cross sections for the double photoionization into the {3s3p^5} {^1P}, {^3P} states of Ar^{+ +} are presented for exciting photon energies between threshold and 120 eV. In the threshold range the energy dependencies of these cross sections were determined for the first time. Singlet and triplet states are populated with comparable probabilities at equal excess energies, in contrast to predictions of the extended Wannier ...
Aufsatz
Precision laser spectroscopy of the ground state hyperfine splitting of hydrogenlike ^209 Bi^82+
(1994)
The first direct observation of a hyperfine splitting in the optical regime is reported. The wavelength of the M1 transition between the F = 4 and F = 5 hyperfine levels of the ground state of hydrogenlike ^209 Bi^82+ was measured to be \lamda_0 = 243.87(4) nm by detection of laser induced fluorescence at the heavy-ion storage ring ESR at GSI. In addition, the lifetime of the laser excited F = 5 sublevel was determined to be \tau_0 = 0.351(16) ms. The method can be applied to a number of other nuclei and should allow ...
Aufsatz
Double-autoionization decay of resonantly excited single-electron states
(1993)
Perturbation theory in the lowest non-vanishing order in interelectron interaction has been applied to the theoretical investigation of double-ionization decays of resonantly excited single-electron states. The formulae for the transition probabilities were derived in the LS coupling scheme, and the orbital angular momentum and spin selection rules were obtained. In addition to the formulae, which are exact in this order, three approximate expressions, which correspond to illustrative model mechanisms of the transition, ...