The ejected-electron spectra corresponding to the radiationless decay of 5p5 states in Ba atoms have been measured precisely for different incident electron energies ranging from the appearance of the first autoionizing line at 15.68 eV up to 140 eV. The spectra have been obtained at an observation angle of 54.7° and with incident-electron and ejected-electron energy resolutions of 0.2 eV and 0.07 eV, respectively. In total, 63 lines with excitation thresholds below 22 eV have been observed between 9.8 and 16.6 eV ejected-electron kinetic energy. Based on measured excitation energies, intensity behavior of lines, calculated excitation energies, cross sections and decay rates of states in 5p56s , 5p55d and 5p55d6snl configurations, assignments for all 63 lines are proposed. The excitation and decay processes for classified autoionizing states have been examined and compared with existing data. The excitation threshold of the subshell has been established at 15.61 ± 0.05 eV.

The ejected-electron spectra arising from the decay of the 4p nln l n l 5 ¢ ¢   autoionizing states in Sr atoms have been studied precisely at the incident-electron energies close to excitation and ionization thresholds of the 4p 6 subshell. The excitation behaviors for 58 lines observed between 12 and 21eV ejected-electron kinetic energy have been investigated. Also, the ab initio calculations of excitation energies, autoionization probabilities and electron-impact excitation cross sections of the states 4p nln l n l 5 ¢ ¢   (nl = 4d, 5s, 5p; n l ¢ ¢ = 4d, 5s, 5p; n l   = 5s, 6s, 7s, 8s, 9s, 5p, 6p, 5d, 6d, 7d, 8d, 4f, 5g) have been performed by employing the large-scale configuration-interaction method in the basis of the solutions of Dirac-Fock-Slater equations. The obtained experimental and theoretical data have been used for the accurate identification of the 60 lines in ejected-electron spectra and the 68 lines observed earlier in photoabsorption spectra. The excitation and decay processes for 105 classified states in the 4p 5 5s nl 2 , 4p 5 4d nl 2 and 4p 5 5snln l ¢ ¢ configurations have been considered in detail. In particular, most of the states lying below the ionization threshold of the 4p 6 subshell at 26.92eV possess up to four decay channels with formation of Sr + in 5s 1 2 , 4d 3 2,5 2 and 5p 1 2,3 2 states. Two-step autoionization and two-electron Auger transitions with formation of Sr 2+ in the 4p 6 S 1 0 ground state are the main decay paths for high-lying autoionizing states. The excitation threshold of the 4p 6 subshell in Sr has been established at 20.98±0.05eV.

Large scale configuration interaction calculations of energy levels, autoionization probabilities and electron-impact excitation cross sections of the autoionizing states 4p5nln′l′ (nl = 5s,4d,5p,4f; n′l′ = 4d,5s,5p,5d,5f,5g,6s,6p,6d,7s,7p) of Rb up to 19.6 eV were performed for the first time. The relativistic effects were taken into account in the Dirac–Fock–Slater approximation. The asymmetry parameters of the angular distribution of Auger electrons for a number of electron-impact excited states were calculated in a single configuration intermediate coupling approximation. Strong dependence on the energy of exciting electrons was found for the angular distribution of the emitted Auger electrons from the states with J > 3/2 at the polar ‘magic angle’ of 54.73°. The calculated data were used for the novel classification of lines in an experimental ejected-electron spectrum.

Theoretical investigation of the 5p5 nl(L1S1)n'l' LSJ autoionizing states of Cs was performed by using large scale configuration interaction calculations of energy levels, autoionization probabilities and excitation cross sections obtained in the Dirac–Fock–Slater approximation. Classification of calculated energy levels in the LSJ coupling scheme of angular momenta and simulation of the intensities of ejected Auger electron spectrum were performed. The classified energy levels in the region from the excitation threshold up to 17.365 eV and simulated intensity spectrum were used for identification of the experimental ejected-electron spectrum of Cs excited by 30 eV electrons.

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