Negative ion calculations based on many-body theory

The resonance structures of electron interaction with Sr and Ba atoms: low-energy electron scattering and photodetachment of the negative ions

“…The cusp around 1.7 eV in the detachment channel (5s 2 1 S + kd) 2 D and the broad maximum around 2.0 eV of the (5s5p 3 P o +kp) 2 D channel reflect the channel interaction and are quite sensitive to the positions of the thresholds of 3 P o and 3 D. From figure 9, it can be seen more clearly that the third 0 0 . 5 5, except that the results of Gribakin et al [6] for the ionization channel 1 S + kd are represented by a long-dashed curve for the length form and a dot-dashed curve for the velocity form.…”

“…The growing interest in the study of electron scattering with alkaline-earth atoms and the photodetachment of alkaline-earth negative ions has been stimulated by the discovery that one of these closed-shell atoms forms stable negative ions [1,2]. The studies include the binding energies of the negative ions [3][4][5][6][7][8][9][10][11][12][13][14], low-energy electron collisions with alkaline-earth atoms [15][16][17][18][19][20][21][22][23][24][25] and the photodetachment of the very loosely bound alkaline-earth negative ions [26][27][28][29][30][31][32][33][34]. Among those studies, only a few of them concerned low-energy electron interaction processes with Sr and Ba atoms.…”

“…Detailed contributions of the individual ionization channels to the 2 D partial wave photodetachment cross sections of Sr − ions. The meanings of the curves are the same as in figure5, except that the results of Gribakin et al[6] for the ionization channel 1 S + kd are represented by a long-dashed curve for the length form and a dot-dashed curve for the velocity form.…”

The resonance structures in the cross sections of slow electron interaction with barium atoms: a fully relativisticR-matrix study

“…The interest in the study of the electron scattering with alkaline-earth atoms and the photodetachment of their negative ions was stimulated by the fact that Ca and other heavier alkaline-earth atoms can form stable negative ions [1,2] by absorbing an extra electron outside a closed shell. These studies include the binding energies of the negative ions [3][4][5][6][7][8][9][10][11][12][13][14][15][16], low-energy electron collisions with alkaline-earth atoms [17][18][19][20][21][22][23][24][25][26][27][28][29][30] and the photodetachment of the very loosely bound alkaline-earth negative ions [31][32][33][34][35][36][37][38]. Among these studies, only a few of them were concerned with the low-energy electron interaction process with barium atoms.…”

Positron binding to calcium, a configuration interaction study

“…Both theoretical and experimental evidence for the existence of the Ca − 4s 2 4p ground state were first presented in 1987 [1,2]. This result stimulated a lot of theoretical activity and it was quickly shown that both strontium and barium could also form stable negative ions [3][4][5][6]. In this letter, it is demonstrated that positronic calcium is electronically stable and therefore that calcium can bind a positron as well as an electron.…”