Excitation of the lowest-lying autoionising level in Cs I

Threshold truncation of a giant dipole resonance in photoionization of Ti3+

“…Both pairs accumulate considerable resonance strength and are therefore-by analogy with PI of Sc 2+ [5]-identified with 3p 6 3d 2 D → 3p 5 (3d 2 3 P) 2 P and 3p 6 3d 2 D → 3p 5 (3d 2 3 F) 2 D excitations, respectively. The theoretical results of Gorczyca et al [16] and Tiwary et al [17], who find similar strengths for these transitions, support this interpretation, although the corresponding resonance energies differ by up to 3.5 eV. The remaining resonances are most likely due to 3p → 4s transitions and are assigned in the order of increasing resonance energy by comparison with the theoretical results [17].…”

“…The theoretical results of Gorczyca et al [16] and Tiwary et al [17], who find similar strengths for these transitions, support this interpretation, although the corresponding resonance energies differ by up to 3.5 eV. The remaining resonances are most likely due to 3p → 4s transitions and are assigned in the order of increasing resonance energy by comparison with the theoretical results [17]. However, the poor agreement between experimental and theoretical resonance energies and strengths brings this assignment into question.…”

“…The available theoretical results differ from one another by up to 1.1 eV. For the ( 3 F) 2 F, ( 3 P) 2 P, and ( 3 F) 2 D terms of the 3p 5 3d 2 configuration Gorczyca et al [16] calculated resonance energies of 46.29, 50.72 and 51.13 eV, respectively, and the theoretical results of Tiwary et al [17] for the same resonances are 44.8, 47.9 and 50.2 eV. Both calculations make predictions for the ( 3 F) 2 F resonance position that differ by more than 1 eV from the measured value, and both theories ignore the fine-structure splitting of the terms that is partly observed in the present experiment.…”

Electron impact excitation cross sections of sodium autoionizing state from threshold to 1.5 keV

“…An indication of the resonance structures have also been observed in the excitation functions for other autoionizing states with a hole in the outer p subshell of alkali atoms decaying either via electron ejection (Feldman and Novick 1967, Pejcev and Ross 1977, Borovik et al 1989, or radiatively (Aleksakhin et al 1981). No theoretical interpretation of the resonances was given, although some calculations show a sharp increase of the excitation cross sections near the threshold (Rabik 1975, Srivastava and Rai 1977, Tiwary 1983a, Pangantiwar and Srivastava 1987, Theodosiou 1987, Borovik et al 1993. It was noted that within the DWBA this increase can be caused by the exchange scattering (Rabik 1975, Tiwary et al 1985, Pangantiwar and Srivastava 1987, Borovik et al 1993 in combination with the enhancement of the direct amplitude (Pangantiwar andSrivastava 1987, Borovik et al 1993).…”

Calculation of energy differences and oscillator strengths for the electric-dipole transitions of sulphur

“…However, as the number of configurations increases the problem quickly becomes too complicated to handle. Many CI calculations have been performed for the light atoms (Biemont et al 1993, Bell and Hibbert 1990, Fleming et al 1996, Hibbert 1974, some inner-shell excitation transitions (Tiwary et al 1983), the transitions in the fluorine-like ions (Mohan and Hibbert 1991) 0953-4075/97/173873+07$19.50 c 1997 IOP Publishing Ltd and intercombination lines in the zinc-like ions (Fleming and Hibbert 1995). In this paper we report a large-scale CI calculation for the sulphur atom to obtain energy splittings and oscillator strengths for some electric-dipole transitions.…”