Experimental and theoretical study of the Auger cascade following 3d→5p photoexcitation in Kr (original) (raw)
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Angle-resolved study of the Auger electron cascades following the 3d 5/2 → 5p photoexcitation of Kr
Journal of Physics B: Atomic, Molecular and Optical Physics, 2000
The angular anisotropy of Auger electrons from cascade Auger transitions induced by photoexcitation of the 3d −1 5/2 5p resonance in Kr is reported. In contrast to the previously reported measurements for Ne and Ar, a large anisotropy is observed for the first-step spectator transitions 3d −1 5/2 5p → 4s −1 4p −1 5p and 3d −1 5/2 5p → 4s −2 5p while the second-step participator transitions are almost isotropic. These findings are qualitatively explained by consideration of the alignment transfer via the first-step spectator Auger transitions. ¶ On leave from:
Physical Review A, 1996
The anisotropy of the resonant Auger decay of the photoexcited Kr 3d 3/2,5/2 Ϫ1 5p states has been studied by comparing the new high-resolution experimental results with the multiconfiguration Dirac-Fock calculations. The measurements were made with very high photon and electron energy resolutions in the Auger resonant Raman mode giving ''subnatural'' linewidths of ϳ 35 meV, which has enabled us to resolve the fine structures in detail. Comparison with high-quality experimental results allows us to confirm the roles of exchange interaction as well as initial-and final-state interactions in the theoretical description of the angular anisotropy of the resonant Auger transitions. ͓S1050-2947͑96͒08507-1͔
Spin polarization transfer in the resonant Auger decay following Kr 3d 1 5p photoexcitation
Journal of Physics B: Atomic, Molecular and Optical Physics, 2003
Spin polarization of the resonant Auger electrons is measured following the decay of Kr 3d −1 5p states resonantly excited by circularly polarized light. A large polarization transfer is found in particular for all strong transitions to the 4s −1 4p −1 5p and 4s −2 5p states. The experimental results are in excellent agreement with calculations carried out by means of the multiconfiguration Dirac-Fock method.
Two-photon excitation and relaxation of the 3d-4d resonance in atomic Kr
Physical review letters, 2010
Two-photon excitation of a single-photon forbidden Auger resonance has been observed and investigated using the intense extreme ultraviolet radiation from the free electron laser in Hamburg. At the wavelength 26.9 nm (46 eV) two photons promoted a 3d core electron to the outer 4d shell. The subsequent Auger decay, as well as several nonlinear above threshold ionization processes, were studied by electron spectroscopy. The experimental data are in excellent agreement with theoretical predictions and analysis of the underlying multiphoton processes.
Multielectron inner-shell photoexcitation in absorption spectra of Kr: Theory and experiment
Physical Review A, 1993
The probability of Kr 1s photoionization alone and accompanied by 4p, 3d, 3p, 2s, and 2s4p excitations has been calculated as a function of photon energy in the vicinity of the respective thresholds; pertinent energies have been computed including relativistic, quantum-electrodynamic, and relaxation eAects. Sharp features from two-electron excitations are expected in absorption spectra only if at least one of the electrons undergoes a transition to a bound state; this becomes less probable in inner shells.
Complete Auger decay pathways of Kr 3d−1hole levels including direct double processes
Journal of Physics B: Atomic, Molecular and Optical Physics
The detailed level-to-level single and double Auger decay rates of Kr 3d −1 hole states are investigated in the framework of the first and second perturbation theory implemented by distorted wave approximation with the balanced large-scale configuration interaction of the successive ions being taken into account. The branching ratios of cascade and direct double Auger decay to the total probability are predicted to be 16.5% and 16.1%, respectively, for Kr 3d −1 5/2 and 16.8% and 17.2% for Kr 3d −1 3/2 , resulting in total double branching ratios of 32.6% and 34.0% for the two levels of Kr 3d −1 hole. A comparison is made with the available experimental results on the branching ratio into triply charged ions and good agreement was found with the most recent published work. This work represents the first theoretical study to correctly explain the experimental measurements. The complete pathways were depicted by including the direct double Auger decay process. Compared with the Auger decay of Ar 2p −1 , the fraction of the cascade double of Kr 3d −1 is dramatically enhanced yet that of direct double Auger processes is only slightly increased.
Laser excitation combined with 2p photoionization and Auger decay of potassium
Physical Review A, 2006
The 2p photoionization and subsequent L 2,3 M 2,3 M 2,3 Auger decay spectra from free 4s 1/2 → 4p 1/2 laser-excited potassium atoms are studied both experimentally and theoretically. The shake-up-structure of the 2p photoelectron spectrum of K is resolved. A direct experimental way for resolving the satellite structure due to conjugate shake-up transitions accompanying the hole creation in the L 2,3 M 2,3 M 2,3 Auger spectrum of nonexcited atoms is presented. Theoretical ab initio computations based on the multiconfiguration Dirac-Fock approach were performed to interpret the experimental findings.
Strong configuration interaction in the 3p photoelectron spectrum of Kr
Physical Review A, 2020
We measured the Kr photoelectron spectrum in the region close to the 3p3p3p ionization threshold. Our high-resolution measurements allowed a clear observation of spectral structures due to electron correlation effects. Analysis based on relativistic multiconfiguration calculations could explain these observed peaks as due to strong configuration interactions between the 3pensuremath−13{p}^{\ensuremath{-}1}3pensuremath−1 state and 3densuremath−2nl3{d}^{\ensuremath{-}2}nl3densuremath−2nl states. Calculated and experimental data for peak assignments and intensity distributions are in good agreement. In addition, we measured the anisotropy parameter ensuremathbeta\ensuremath{\beta}ensuremathbeta, which also agreed well with theory. These findings provide a detailed view of strong configuration interactions between the 3pensuremath−13{p}^{\ensuremath{-}1}3pensuremath−1 and 3densuremath−2nl3{d}^{\ensuremath{-}2}nl3densuremath−2nl inner-shell hole states.
High-resolution x-ray-emission study of 1s4p and 1s3d two-electron photoexcitations in Kr
Physical Review a, 2014
High-energy-resolution photoexcited KN 2,3 x-ray-emission measurements were carried out on krypton with the excitation energy tuned around the 1s4p and 1s3d double-excitation thresholds. Comprehensive two-dimensional resonant inelastic x-ray-scattering maps were recorded for the range of excitation and emission energies corresponding to both types of double excitations. The double-excitation signal could be clearly resolved from the dominant 1s ionization signal. The latter was subtracted from the measured maps, yielding isolated 1s4p and 1s3d photoexcitation spectra. Both two-electron excitation spectra are well described by a model spectrum built of consecutive bound-bound discrete transitions and shake-up and shake-off channels giving precise energies and intensities of the corresponding contributions. The obtained results are compared with other existing experimental values based on x-ray-absorption measurements and theoretical predictions.
Angular distribution of ejected electrons in resonant Auger processes of Ar, Kr, and Xe
Physical Review A, 1989
Angle-resolved electron spectroscopy with the help of synchrotron radiation has been used to study resonant Auger processes near the core shells of Ar2p, Kr3d, and Xe4d. Results for the lowest-energy resonances have received special attention: argon (Ar 2p3/2 +4s) at a photon energy of 244.4 eV, krypton (Kr 3d&&2~5p) at 91.2 eV, and xenon (Xe 4d5&&~6p) at 65.1 eV. The angular distribution parameters P are evaluated for each of the resolved Auger peaks. Most striking is the occurrence of large negative P values for some of the higher kinetic energy peaks. The results are most apparent under high electron resolution. The theoretical basis for having P values near-1 is discussed. In particular, the experimental results for argon are found to be in general agreement with the prediction of-1 P values by using either angular momentum transfer theory or normal Auger theory. However, a better understanding of the range of P values will have to await explicit calculations. Experimental results on the Auger spectra are also given at lower kinetic energies, for shakeup states, and for higher-energy resonances, especially those involving vacancies in the core shells of the lower spin states. It is shown that, although transitions having the same final state of the singly charged ion frequently have similar relative intensities and P values, occasionally they dift'er quite markedly. The theoretical consequences of variant behavior for processes having the same final states are also discussed.