J. Phys. IV France 04 (1994) C9-401-C9-404
Argon 3s autoionizationS.L. Sorensen1, T. Åberg2, J. Tulkki3, E. Rachlew-Källne1, G. Sundström1 and M. Kirm4
1 Department of Physics I, Royal Institute of Technology, 10044 Stockholm, Sweden
2 Laboratory of Physics, Helsinki University of Technology, 02150 Espoo, Finland
3 Optoelectronics Laboratory, Helsinki University of Technology, 02150 Espoo, Finland
4 Department of Atomic Spectroscopy, University of Lund, 22362 Lund, Sweden
Synchrotron radiation-excited ion mass spectrometry has been used to study the 3s3p6np (n≥4) resonances in argon at 25.0 - 29.3 eV. It is shown using a time-independent resonant scattering approach that the Fano formalism may be applied to overlapping resonances. For the Dubau-Seaton profile an exact expression of the closed-channel phase shift is obtained. We find that regarding the window character of the Ar 3s series the Fano parameters calculated using the multichannel multiconfiguration Dirac-Fock method are in good agreement with those derived from fitting a convoluted Fano function to the measured n = 4 autoionizing resonance. The Fano parameters are also derived from fits to the 5≤n≤8 resonances which tests the validity of this parametrization to overlapping members of an inner-valence electron resonance series. In contrast, a parametrization of the entire series based upon the Dubau-Seaton formula did not result in a good fit without modifications. Using the same value of the shape parameter we find, however, that the n = 4 resonance can be accurately represented by both the Fano and Dubau-Seaton profiles.
© EDP Sciences 1994