R-matrix calculation of the photoabsorption of K II, Ca III and Sc IV

Abstract

The R-matrix approach is employed to study the photoionization of the argon-like ions K II, Ca III and Sc IV. The 3s3p 6 np 1 P o Rydberg series is identified for each ion. Excellent agreement with previously published resonance positions is observed but the q-reversal reported for Ca III by van Kampen et al is not replicated in this calculation. Good agreement with experimental data is observed for K II but not for Ca III. The differences in shape of the total cross sections along the sequence are attributed to the relative positions of the 3s and 3p Cooper minima.

Oscillator Strengths for K III, Ca IV and Sc V

“…3p 6 3s3p 6 ; nl 3s 2 3p 4 3 Pnl; nl H 3s 2 3p 4 1 Dnl; nl HH 3s 2 3p 4 1 Snl; OP Opacity Project; l length form; v velocity form). present authors [11] in which K III target state energy levels were calculated prior to evaluation of photoionization cross sections for K II, and with experimental data compiled by Corliss and Sugar [12]. We have, however, only included experimental data for three of the lower energy states, since the values for higher states are uncertain.…”

Variation of 3sPhotoionization Resonance Structures in a Serial Atomic Number Species Ar, K, and Ca

“…np excitations of Ar isoelectronic sequence, a dramatic change of the resonance shape along with the change of atomic number has been reported. [12][13][14][15] In a previous paper, we reported the window resonances of heavier alkaline atoms K, 16) Rb, and Cs. 17) The window resonance of these species were found to be distinctively broader compared with their neighboring rare gas atoms.…”

New Window Resonances in the Potassium 3sPhotoabsorption Spectrum

“…In particular, the subvalence s-shell photoexcitation in rare gas atoms [5][6][7][8][9][10][11][12][13][14][15] and closely related species [18][19][20][21] have been noted for the window type resonances, appearing as dips in the continuum background of the photo-absorption spectrum. Window resonances are extreme cases of the Beutler-Fano profile with profile index q close to zero.…”

“…Autoionizing resonances of atoms, involving configuration mixing of discrete excited states with direct ionization continua, have been studied intensely since the first measurement of the double photoexcitation resonances of helium with synchrotron radiation. In particular, the subvalence s-shell photoexcitation in rare gas atoms [5][6][7][8][9][10][11][12][13][14][15] and closely related species [18][19][20][21] have been noted for the window type resonances, appearing as dips in the continuum background of the photo-absorption spectrum. Window resonances are extreme cases of the Beutler-Fano profile with profile index q close to zero.…”