A close look at Ar photoion spectra around the K edge: non-diagram transitions and double photoionization

Abstract

Relative abundances of the various ionic charges resulting from photoionization of argon by monochromatked synchrotron radiation at energies between 3150 and 4900 eV have been measured with low statistical error. Despite the fact that already, right at the onset of K excitation (3203.5 eV), almost the full Is binding energy is deposited in the atom, the relative abundances change smoothly over the region of np excitation up to 6 eV above the limit. While this behaviour, caused by Rydberg shake-off (about 0.5 probability at the Is -4p resonance) and by recapture ofthephotoelectron via post-collision interaction, appeanta be undentoodthereinnoexplanation foragradualchange of relative abundances extending over tens of eV below the lowest K excitation. K + M and K + L single photon double excitations both show up as a smooth rise of the average ionic charge c j from the respective threshold to a plateau at considerably higher energy, the overall increase of being 0.206+0.02 and 0.13*0.01.

Investigation of the cascades in atoms using the global characteristics of spectra

“…The formulae for the two-electron matrix elements are given, for example, in [92,93], and their direct summation can be accomplished easily. The total line strength of radiative transitions (10) and the total Auger transition rate (12), (13) consist of the statistical multipliers, depending on the numbers of electrons in the active shells or subshells, and of the one-or two-electron quantities, depending only on the radial orbitals of these electrons. It enables the extrapolation of the global characteristics for the other transitions between the same shells (subshells) of the same element as well as for the same transitions in the atoms of different elements.…”

“…They give the dependence of the intensities of various ions on the photon energy. The more refined data are obtained when using the coincidence technique [10][11][12][13][14][15][16]. The photoelectron-photoion coincidence experiment enables one to separate the charge state distribution corresponding to the creation of a vacancy in a given subshell.…”

“…The charge state and photoion spectra were studied for Ne [3,49], Ar [4,11,12,[50][51][52][53], Kr [5,6,33,[53][54][55][56], Xe [6,9,16,34,35,46,[57][58][59][60], and for all of them [61][62][63]. Also such spectra were investigated for lanthanides [7-9, 15, 32, 64-66], Mg [50,67], Al, Si, S, Ca, Fe [50], Cu [18], Sr [68], Ba [69], Au [70], Re [71], and Ta [71].…”

Computation of Ion Charge State Distributions After Inner-Shell Ionization In Ne, Ar And Kr Atoms Using Monte Carlo Simulation

“…Radiative (CSD) of ions produced by the inner-shell transitions are due to displacement of vacancies to higher photoionization of rare gas atoms were performed at shells, while non-radiation transitions are accompanied some restricted energies of the photons that could be by ejection of an electron from the atomic sub-shells obtained from use of an x-ray tube [1][2][3][4]. The decay of inner-shell [10]. The de-Monochromatic synchrotron radiation sources are now excitation of this inner-shell hole via successive radiative being used for detailed studies of the ion charge state (x-ray) and non-radiative (Auger and Coster-Kronig) distributions as a function of the exciting photon energy transitions leads to highly charged ions.…”

The evolution of inner-shell multielectronic X-ray spectra from threshold to saturation for low- to high-Z atoms

“…This, in turn, is due to the low cross-sections of ME transitions in atoms even in the isothermal regime, and their even lower crosssections near threshold. The few existing studies employ mostly electron emission (Armen et al, 1985;Wark et al, 1991), X-ray absorption (Deutsch and Hart, 1986;Gomilsek et al, 2001;Schaphorst et al, 1993), and photoion (Doppelfeld et al, 1993;Levin et al, 1990) spectra. Most of the atoms studied until the last few years were low-Z (mostly light alkali metals) and inert gas atoms, which require only relatively simple calculations.…”