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Volume 13: Pages 307-324, 2000
Experimental and Theoretical Auger and Autoionization Spectra for Electron Impact on Laser‐Excited Ba Atoms
J. Nienhaus 1, W. Mehlhorn 1, O. I. Zatsarinny 2
1Fakultät für Physik, Universität Freiburg, 79014 Freiburg, Germany
2Institute of Electron Physics, 294016 Uzhgorod, Ukraine
We present high‐resolution experimental Auger and autoionization spectra in the energy range 5.6 to 17 eV for 5p ionization/excitation of Ba(6s2) and of laser‐excited Ba*(5d6s 1,3D2) and Ba*(6s6p 1P1) by 1.5 keV electron impact. The wave‐functions and energies of Auger states for 5p ionization of ground‐state and laser‐excited Ba are calculated by the many‐configuration Hartree‐Fock method with relaxed nonorthogonal radial orbitals for different configurations and including relativistic effects through the Breit‐Pauli Hamiltonian. We have also evaluated the 5p ionization cross sections in sudden approximation and the decay rates of the Auger states. The experimental spectra in the energy range 5.6 to 11 eV are due to the Auger decay following 5p ionization and are well predicted by the present theory. The spectra in the energy range 11 to 17 eV, however, are mainly due to the autoionization decay following a 5p excitation. These spectra cannot be understood by the present calculation, which considers only 5p ionization.
Keywords: auger decay, autoionization, laser‐excited atoms, Ba atom, structure calculation, MCHF calculation
Received: May 1, 2000; Published online: December 15, 2008