Integral cross sections and transport properties for electron-mercury scattering over a wide energy range (0.001-1000 eV) and reduced electric field range (0.01-1000 Td)

Abstract

Abstract: We report calculations for electron-mercury scattering using a complex relativistic optical potential method. The energy range of this study is 0.001-1000 eV, with results for the elastic (and momentum-transfer) cross section, summed discrete electronic-state integral excitation cross sections and electron-impact ionization cross sections being presented. Here we obtain our cross sections from a single theoretical relativistic calculation. Since mercury is a heavy element, a relativistic treatment is very desirable. These ab initio calculations are compared to the cross section set recommended by Mirić et al. (Eur Phys J D 71:1, 2017), which were developed from a variety of experimental and theoretical sources. Significant differences are noted between the total excitation and ionization cross sections, and the low-energy momentum-transfer cross section. Electron transport coefficients are subsequently calculated for reduced electric fields ranging from 0.01 to 1000 Td, using a multiterm solution of Boltzmann's equation. The results were compared against those calculated with the Mirić et al. set, and experimental measurements where possible. Overall, there is good agreement demonstrated between both cross section sets and experiment. The drift and diffusion coefficients calculated with the ab initio cross section set were generally lower than those calculated with the Mirić et al. set, at low reduced field strengths E/ N< 2 Td, and vice versa for reduced fields strengths E/ N> 2 Td. The ionisation coefficient calculated here was smaller than that of Mirić et al. and the experimental measurements over the full range of electric fields investigated. Graphical Abstract: [Figure not available: see fulltext.].