Excitation of the $6p7s{}^{3}P_{0,1}$ states of Pb atoms by electron impact: Differential and integrated cross sections

Experimental measurements of electron impact excitation of the $6p7s{}^{3}P_{0,1}$ states of Pb atoms have been made at incident electron energies $E_0=10$, 20, 40, 60, 80, and $100\mathrm{eV}$ and scattering angles from 10° to 150°. In addition, relativistic distorted-wave calculations have been carried out at these energies. The data obtained include the differential (DCS), integral $\left(Q_I\right)$, momentum transfer $\left(Q_M\right)$, and viscosity $\left(Q_V\right)$ cross sections. Absolute values for the differential cross sections have been obtained by normalizing the relative DCSs at 10° to the experimental DCS values of [S. Milisavljević, M. S. Rabasović, D. Šević, V. Pejčev, D. M. Filipović, L. Sharma, R. Srivastava, A. D. Stauffer, and B. P. Marinković, Phys. Rev. A 75, 052713 (2007)]. The integrated cross sections were determined by numerical integration of the absolute DCSs. The experimental results have been compared with the corresponding calculations and good agreement is obtained.

Figure 1

Energy-loss spectrum of lead at $20\mathrm{eV}$ electron-impact energy and 60° scattering angle.

Figure 2

(Color online) Differential cross sections for the $6p7s{}^{3}P_{0,1}$ excitation of lead at (a) $10\mathrm{eV}$, (b) $20\mathrm{eV}$, and (c) $40\mathrm{eV}$ electron-impact energies. Filled circles with error bars denote the present experimental results. The solid line shows DCSs calculated by the MCGS approximation and the dashed line shows the results obtained using the SCGS approximation. The open squares represent the results obtained by Williams and Trajmar [6] and the dash-dotted line shows MCGS calculation for the $6p7s{}^{3}P_0$ excitation.

Figure 3

(Color online) As for Fig. 2 except for (a) $60\mathrm{eV}$, (b) $80\mathrm{eV}$, and (c) $100\mathrm{eV}$ electron-impact energies.

Figure 4

(Color online) (a) Integral, (b) momentum transfer, and (c) viscosity cross sections for electron-impact excitation of the $6p7s{}^{3}P_{0,1}$ states of lead atom. Experiment and theory are as for Fig. 2. Open circles denote MCGS calculations for the $6p7s{}^{3}P_0$ excitation.