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[en] Do we really understand the phenomenon of autoionization in atoms sufficiently well to consider it a ''mature'' topic. Can we generalize our understanding to predict behavior in systems not yet studied. Can we extract physical understanding from the encouraging results of the ''many-body calculations''. Or must we still try to understand one atom at a time. Molecular autoionization is clearly more difficult. Not only must we content with ''vibrational autoionization'' as well as ''electronic autoionization'', but the competing process of predissociation must also be taken into account. In this molecular domain, we have many experiments and many phenomena. The extant theories only deal with some cases, and are not yet able to explain some prominent observations. A group consisting of theorists and experimentalists active in the field of autoionization assembled at Argonne National Laboratory for a two-day Workshop on May 2-3, 1985, to try to provide some consensus of our present understanding and to point out the most promising direction for progress in the near future. Abstracts of individual items from the workshop were prepared separately for the data base
[en] Rydberg spectra of the chlorine atom, 3s23p4(3P)ns, J = 1/2, 3/2, and 5/2, are calculated by use of an eigenchannel quantum defect method. The results indicate that the channel interactions due to electrostatic and spin-orbit potentials are weak. The effect due to channel interaction of the 3s3p6 configuration is completely negligible. Agreement with emission data is excellent (< 0.2% accuracy except for the lowest n = 4 levels). Autoionization resonances are predicted
[en] A theory of the post-collision interaction (PCI) is developed for the case when an electron-atom impact results in the creation of two low-energy Wannier electrons and an ion excited into an autoionizing state. The following autoionization decay exposes the Wannier pair to the influence of PCI resulting in the variation of the shape of the line in the autoionization spectrum. An explicit dependence of the autoionization profile on the wavefunction of the Wannier pair is found. PCI provides an opportunity to study this wavefunction for a wide range of distances. (Author)
[en] Analysis of the coupling matrix elements between quasibound and free states of doubly excited helium provides an unambiguous mechanistic interpretation of autoionization by electron correlation. The analysis is based on the dependence of the integrand of the matrix elements on the distances r1 and r2 and the angle theta12, and on the separation of the total amplitude into a part containing only one-electron operators and a part comprising 1/r12. The former gives rise to the normally dominant part, a generalized S/sub N/-2 mechanism; the latter, usually a smaller part, is the direct electron-electron, binary-collision contribution
[en] We investigated the autoionization spectra of atomic samarium by the three-step excitation and measured the energy levels of the odd autoionization states located in the region of 48800 cm-1 - 51200 cm-1. More than fifty autoionization states were found in the investigated range. Among the observed lines, some lines were analyzed by Fano's formula and q parameters were measured.
[en] It is shown for the first time that the use of autoionisation states for phase matching leads to the efficient selection of a single harmonic generated in a plateau region in plasma. The selected harmonic frequency can be tuned by changing the relative concentration of plasma components and tuning the fundamental radiation frequency. It is shown that the contrast of the selected harmonic can exceed 104. (special issue devoted to the 80th birthday of S.A. Akhmanov)
[en] We calculate the fraction of ionization numerically as functions of laser frequencies for situations in which divalent atoms or irons, resonantly excited via absorption of two photons of a laser with intensity I1 and frequency ω1, is ionized with absorption of another photon of either the same laser or a second laser with intensity I2 and frequency ω2 through autoionizing resonances. Our results suggest that the autoionization resonance profiles from resonantly excited states may be modified depending on the laser conditions, without any laser induced change in the coupling of bound and continuum configurations, or any phase-related interference effects.
[en] We report a measurement of the branching ratio for production of 5d3/2 ions in various mj states following the autoionization of the (6p1/2nd5/2)J=MJ=3 states of barium in an electric field. By detecting the population in different ion states, rather than the electron distribution, we are able to measure the decay routes even in the presence of an electric field. These branching ratios show pronounced new structure, even at fields as low as 30 V/cm