Electron-impact ionization of the inner subshells of uranium

Fully relativistic first-order perturbation theory calculations are made for the electron-impact ionization of the inner $K$, $L$, and $M$ subshells of uranium. One set of calculations only includes the two-body electrostatic interaction, while the other set includes the full two-body retarded electromagnetic interaction. The $K$ subshell calculations show large differences between the two sets of calculations, the $L$ subshell calculations show moderate differences, and the $M$ subshell calculations show small differences. The $M$ subshell calculations fall within the error bars of recent measurements [A. Moy et al., J. Phys. B 47, 055202 (2014)].

Figure 1

Electron-impact ionization of ${\mathrm{U}}^{90+}$. Solid red line, SCADW electrostatic; dashed green line, SCADW retarded electromagnetic; blue circle with error bar, experiment [12] ($1.0 \mathrm{b} = 1.0\times {10}^{-24} {\mathrm{cm}}^2$).

Figure 2

Electron-impact ionization of the $K1$ subshell of uranium. Solid red line, SCADW electrostatic;

dashed green line, SCADW retarded electromagnetic ($1.0 \mathrm{b} = 1.0\times {10}^{-24} {\mathrm{cm}}^2$).

Figure 3

Electron-impact ionization of the $L$ subshells of uranium: (a) $L1$, (b) $L2$, and (c) $L3$. Solid red line, SCADW electrostatic; dashed green line, SCADW retarded electromagnetic ($1.0 \mathrm{b} = 1.0\times {10}^{-24} {\mathrm{cm}}^2$).

Figure 4

Electron-impact ionization of the $M$ subshells of uranium: (a) $M1$, (b) $M2$, (c) $M3$, (d) $M4$, and (e) $M5$. Solid red line, SCADW electrostatic; dashed green line, SCADW retarded electromagnetic; blue circles with error bars, experiment [11] ($1.0 \mathrm{b} = 1.0\times {10}^{-24} {\mathrm{cm}}^2$).