Angular distribution of the fluorescence radiation of Kr II satellite states

Abstract

Photon-induced fluorescence spectroscopy was applied for the first time to investigate the anisotropy of VUV radiation emitted from Kr II satellite states with total angular momentum J 3 2 after the photoionization of the Kr atom by linearly polarized synchrotron radiation near the 4s threshold. The measurements showed that the sign of the alignment parameter is practically independent of the exciting-photon energy for the ionic state with J = 5 2 , whereas for the states with J = 3 2 the alignment parameter changes sign with varying energy. Simple formulae connecting the angular distribution parameter and the alignment parameter with the kinematics of our experiment and with quantities describing the dynamics of the photoionization were derived in closed form. Partial and total cross sections for the photoionization of 4p, 4s and several satellite levels were calculated taking into account many-electron correlations and doubly-excited states. For the satellite states with J 3 2 the dependence of the angular distribution parameter on the exciting-photon energy was calculated. Good overall agreement between theory and experiment was obtained.

Coherence and correlations in photoinduced Auger and fluorescence cascades in atoms

“…The resulting change of the screening (i.e., the main part of the PCI) will lead to a decreasing energy of the photoelectron or even to its recapture into a discrete Rydberg state of the ion. This phenomenon is well studied both experimentally (van der Wiel et al, 1976;Eberhardt et al, 1988;Samson et al, 1996Samson et al, , 1997Lu et al, 1998;LeBrun et al, 1999;Hentges et al, 2004) and theoretically Armen et al, , 1997Sheinerman, 2003). It is known that in general the photoionization and the PCI-induced recapture of the photoelectron should be considered as a one step process leading to the valence-excited ionic states.…”

“…The alignment parameter A 20 (J ) is then obtained in the standard way by using expression (41) of Section 3 (Berezhko and Kabachnik, 1977;Balashov et al, 2000). This method was applied, for instance, in experiments using SR beam-lines at BESSY I and II in Berlin delivering rotatable linear polarization of the exciting photons, which makes it possible to perform experiments at a fixed spectrometer geometry Schmoranzer et al, 1997;Ehresmann et al, 1998;Demekhin et al, 2005). The main advantage of this method is that it can be applied not only in the visible, but also in the VUV wavelength region, where the possibility to use transmission filters and optics is strongly reduced.…”

“…Several approaches have been developed in order to describe the PCI phenomena in the near-threshold photoionization: semiclassical models summarized by Russek and Mehlhorn (1986), see also van der Straten et al (1988); several fully quantum-mechanical theories, such as diagrammatic many-body theory Kuchiev and Sheinerman, 1985Sheinerman, 2003Sheinerman, , 2005 or the resonant-scattering theory (Åberg, 1980;Armen, 1988;Armen and Levin, 1997). In quantum-mechanical descriptions, the Green's functions are used to describe the propagation of the intermediate state.…”

Strong interference effects in the angularly resolved Auger decay and fluorescence emission spectra of the core-excited NO molecule

“…The photon-induced fluorescence spectroscopy (PIFS) has already been applied for polarization analysis of atomic fluorescence [4,23] and for studying core-excited molecules [8,18]. The present experimental setup is similar to experiments of [18,23].…”

“…One should note that in the case of closed shell molecules as, e.g., CO, the cross terms in the fluorescence angular distribution parameter (11) are forbidden [8], similar to the fluorescence angular distribution parameter of the closed shell atoms [6,7,23].…”