Photoionization of atoms using synchrotron radiation

Abstract

A comprehensive review is given on photoionization of rare gas atoms using monochromatized synchrotron radiation. Emphasis is put upon the general experimental and theoretical background, and illustrative examples are presented in order to show the present status and the progress in the field during the last decade.

Double ionization of atomic cadmium

“…The main decay channels for the 4s hole are expected to involve states of the 4p −1 4d −1 , 4d −2 and 4d −1 5s −1 configurations [42], which is confirmed by observation of the 4s photoelectron, identified by the ∼7 eV broad band at around 85 eV electron kinetic energy, as observed in the electron distributions of the states mentioned. The 4p −1 4d −1 states created in this way can be expected to rapidly undergo CosterKronig decay leading to 4d −3 states [11], which is confirmed by preliminary analysis of the triple electron coincidences that are also recorded in our experiment.…”

Influence of double Auger decay on low-energy 3dphotoelectrons of krypton

“…The calculations have been carried out using Eq. (9) with a resonance width 1 ≡ (3d 3/2 ) = (3d 5/2 ) = 88 meV [33] and a width of the intermediate state 2 = 73 meV [25]. Apart from this we used values for the effective charges of the mean-field potentials obtained by averaging over the electron emission angles.…”

“…Particular attention has been paid to the influences of Auger decay on the photoelectron spectra, which are quite well documented both experimentally and theoretically (see, for instance, the reviews provided by Refs. [1,2]). …”

First observation of a Fano profile following one step autoionization into a double photoionization continuum

“…This is not the case in the single 2p-l, and, even more, in the double photoionization channels where one observes two similar Beutler-Fano profiles, although the absolute values of the cross sections are strongly different in both continua. Since the first observations in single photoionization of helium 1741, many Fano profiles have been observed [14, in single photoionization channels, but it is the first time, to our knowledge, that such a profile is directly observed following a one-step decay of a neutral core-excited state into a double photoionization continuum. Related measurements are the recent observations of Auger transitions contributing to valence double photoionization [79], and of asymmetric photoelectron line profiles [80, 811 in inner-shell shake up satellites lying above the double ionization threshold involving less bound electrons, suggesting a coupling between discrete satellite states with underlying shake off continua.…”

“…[9]. In the two-step process [12][13][14]331, the ejection of the first electron is followed by Auger decay of the singly charged ion. In the double Auger decay, the excess energy is distributed between two electrons that are simultaneously ejected from the singly charged ion, leading to triply charged ions.…”