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Now showing items 51-60 of 62
Aufsatz
High laser field effects in multiphoton ionization of Na_2
(1992)
Femtosecond pump/probe multiphoton ionization experiments on Na_2 molecules are performed. The dependence of the total Na^+_2 ion signal on the delay time and the intensity of the femtosecond laser pulses is studied in detail. It is observed that molecular vibrational wavepacket motion in different electronic states dominates the time dependence of the ion signal. For higher laser intensities the relative contributions from the A ^1 \summe^+_u and the 2 ^1 \produkt__g states change dramatically, indicating the ...
Aufsatz
Femtosecond pump-probe study of the spreading and recurrence of a vibrational wave packet in Na_2
(1992)
The motion of a vibrational wave packet in the bound A(^1 \summe^+_u) electronic state of the sodium dimer is detected in a femtosecond pump/probe molecular beam experiment. For short times harmonic motion is seen in the total ion yield of Na^+_2 as a function of delay time between the two laser pulses. The spreading of the wave packet results in the loss of the periodic variation of the ion signal. For longer delay times (47 ps) the wave packet regains its initial form which is reflected in the revival structure of ...
Dissertation
Das Arbeitshaus Breitenau
(Gesamthochschule Kassel; Verein für hessische Geschichte und Landeskunde e.V., 1992)
Aufsatz
Interchannel interactions and relaxation in the 2p auger spectra of Mg-like ions
(1992)
Relativistic Auger rates for the 2p spectra of Mg-like ions have been calculated in the atomic range 13 < Z < 36. We used the multiconfiguration Dirac-Fock method but beyond a simple frozen-orbital approach we include also relaxation for the bound electrons and the interchannel interaction between the continuum states. Both effects may alter the individual transition rates remarkably. This is analysed for a few selected states within the isoelectronic sequence. Weak transitions within the 2p spectra can be changed ...
Aufsatz
Relativistic effects in physics and chemistry of element 105. [Part] I.
(American Institute of Physics, 1992)
A detailed study of the electronic structure and bonding of the pentahalides of group 5 elements V, Nb, Ta, and element 105, hahnium (and Pa) has been carried out using relativistic molecular cluster Dirac-Slater discrete-variational method. A number of calculations have been performed for different geometries and molecular bond distances. The character of the bonding has been analyzed using the Mulliken population analysis of the molecular orbitals. It is shown that hahnium is a typical group 5 element. In a great ...
Aufsatz
Reduced L_1 level width and Coster-Kronig yields by relaxation and continuum interactions in atomic zinc
(1992)
Calculations of the level width \gamma( L_1) and the f_12 and f_13 Coster-Kronig yields for atomic zinc have been performed with Dirac-Fock wave functions. For \gamma(L_1), a large deviation between theory and evaluated data exists. We include the incomplete orthogonality of the electron orbitals as well as the interchannel interaction of the decaying states. Orbital relaxation reduces the total rates in all groups of the electron-emission spectrum by about 10-20 %. Different, however, is the effect of the continuum ...
Aufsatz
Inclusive probability calculations for the K-vacancy transfer in collisions of S{^15+} on Ar
(1992)
Using the single-particle amplitudes from a 20-level coupled-channel calculation with ab initio relativistic self consistent LCAO-MO Dirac-Fock-Slater energy eigenvalues and matrix elements we calculate within the frame of the inclusive probability formalism impact-parameter-dependent K-hole transfer probabilities. As an example we show results for the heavy asymmetric collision system S{^15+} on Ar for impact energies from 4.7 to 16 MeV. The inclusive probability formalism which reinstates the many-particle aspect ...
Aufsatz
Relativistic effects in physics and chemistry of element 105. [Part] II.
(American Institute of Physics, 1992)
Relativistic self-consistent charge Dirac-Slater discrete variational method calculations have been done for the series of molecules MBr_5, where M = Nb, Ta, Pa, and element 105, Ha. The electronic structure data show that the trends within the group 5 pentabromides resemble those for the corresponding pentaclorides with the latter being more ionic. Estimation of the volatility of group 5 bromides has been done on the basis of the molecular orbital calculations. According to the results of the theoretical interpretation ...
Aufsatz
Electronic structure calculations of small AI_n (n = 2 - 8) clusters
(1992)
The electronic states of small AI_n (n = 2 - 8) clusters have been calculated with a relativistic ab-initio MOLCAO Dirac-Fock-Slater method using numerical atomic DFS wave-functions. The excitation energies were obtained from a ground state calculation of neutral clusters, and in addition from negative clusters charged by half an electron in order to account for part of the relaxation. These energies are compared with experimental photoelectron spectra.