Validation of orientation propensities in electron-impact excitation of lead

Abstract

The atomic orientation J⊥+ generated by polarized-electron impact excitation of Pb(6p2)3P0 → (6p7s)3P1 is studied experimentally using the electron–photon coincidence technique. For the decay transition (6p7s)3P1 → (6p2)3P2, the connection between the polarization components of the emitted photons and the coherence parameters J⊥+, Pl+, γ, h is given. J⊥+ shows a significant dependence on the spin projection of the incident electrons with an energy of 6 eV. The experimental results are compared with theoretical predictions from a semi-relativistic Breit–Pauli R-matrix model and the relativistic distorted-wave approximation and are interpreted with regard to well-established orientation propensity rules. The experimental data show, in agreement with the calculation and the prediction made by a semi-classical trajectory model, that the propensity rules hold for the excitation of the relatively heavy lead atom.

Electron collisions by metal atom vapours

“…Elastic and inelastic scattering had been measured by Williams and Trajmar (1975) only at the energy of 40 eV. Stokes parameters were presented by Herting et al (2003) while single and double ionization by electron impact was investigated by Jha and Roy (2004).…”

Comparison of experiment and theory for superelastic electron-collision studies from laser-aligned magnesium

“…The electron-photon coincidence technique has been used to study collisions with different atomic targets, both experimentally and theoretically. These include the lighter targets hydrogen [4][5][6], helium [7,8], and magnesium [9,10]; intermediate targets including calcium [11][12][13][14][15][16], neon [17][18][19], and zinc [20][21][22][23]; and heavier targets including cadmium [24][25][26], lead [27], and mercury [28][29][30][31][32][33].…”