Electron scattering from magnesium at an incident energy of 20 eV

Abstract

Excitation of the 3 1 P state of magnesium by 20 eV electrons has been studied experimentally using the scattered-electron-polarized-photon correlation method over a wide range of scattering angles (10• -120 • ) and theoretically using the convergent close-coupling and R-matrix with pseudostates methods. The measured linear Stokes parameters, and the circular polarization calculated from these parameters, assuming coherent excitation, are generally well produced by these theoretical models as well as by some previous theories. Relative differential cross sections for elastic scattering and excitation of the 3 1 P and 3 3 P states were also measured over the angular range 10• -140• . The results are compared with those from previous experiments and with present and previous theoretical predictions.

Electron-impact excitation of the 3s3p 1P1 state of magnesium: Electron scattering at small angles

“…At the same electron-impact energies, Brunger et al [4] determined DCSs for the 3s3p 1 P 1 state in the angular range from 5 • to 130 • at energies of 10 and 20 eV and from 3 • to 130 • at 40 eV in 1 • steps at small angles. More recently, Brown et al have studied the 3s3p ( 1 P 1 and 3 P 1 ) states by using the polarized-photon-scattered-electron correlation method and they have obtained the DCS at 40 eV [5] and 20 eV [6] impact energies.…”

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

“…Previous experiments to determine the collision parameters for magnesium were carried out by the Newcastle group [9,10] using the coincidence technique, at an incident energy of 20 eV. The data were compared to both convergent close-coupling (CCC) and R-matrix models, with reasonable agreement found between theory and experiment.…”

“…Here we are interested in the e-Mg scattering system. The CCC method has already been extensively applied to this problem to study the 3 1 P 1 optical excitation function [67], compare with measurement of ACPs at 20 eV [9,10], resolve convergence problems at low energies [10], address discrepancy with experiment for the total ionization cross section [68], and for astrophysical modeling [69]. Consequently, we only give a brief overview of the essential theoretical concepts.…”

“…IV below). The uncertainties in the ACPs calculated in [9,10] were hence relatively large, particularly at higher angles. The superelastic technique allows a more extensive angular survey to be conducted to higher precision than is possible using these conventional coincidence methods.…”

“…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].…”