Polarization spectroscopy of He+(nl)produced in collisions of He2+<

Abstract

Polarization spectroscopy of He + (nl) ion produced in He 2+ -H(1s) collisions in a Debye plasma is studied by the two-center atomic orbital close-coupling (TC-AOCC) method in the energy range 1-200 keV/u. The atomic orbitals and electron binding energies of atomic states are calculated within the Debye-Hückel approximation of the screened Coulomb potential and used in the AOCC dynamics formalism to calculate the magnetic substate-selective electron-capture cross sections. It is demonstrated that the screening of Coulomb interactions affects the entire collision dynamics and the magnitude and energy behavior of m-state-selective cross sections. The changes in magnetic substate-selective electron-capture cross sections when the interaction screening varies introduce dramatic changes in the polarization spectroscopy with respect to the unscreened interaction case. The magnetic substate-selective electron-capture cross sections, as well as the polarization degrees for the 2p 2 P 3/2 -1s 2 S 1/2 ,3p 2 P 3/2 -2s 2 S 1/2 ,3d 2 D 5/2 -2p 2 P 3/2 , and 3d 2 D 3/2 -2p 2 P 1/2 transitions in the He + ion produced in this collision system, are presented and discussed for a number of representative screening parameter values.

Electron capture and excitation processes in H+−H collisions in dense quantum plasmas

“…Its application to collision systems with two or more electrons requires the introduction of appropriate one-electron model potentials for the 'active' electron, V r We note that the TC-AOCC method has been widely used in describing the excitation and electron capture processes in ion-atom collisions in the plasma-free case (see, e.g., [43,44] for references). It has been also used to describe these processes in weakly coupled plasmas with the DH interaction (1) (see, e.g., [9,13,16,[45][46][47][48][49][50]).…”

“…Many theoretical studies of electronic structure and radiative properties of one−electron atomic systems [2,3] and their electron, photon and ion-impact collision processes have been performed using the above screened Coulomb interaction [6][7][8][9][10][11][12][13][14][15][16]. In plasmas with temperatures lower than the electron Fermi temperature…”

Doubly excited states of the hydrogen negative ion and helium atom in astrophysical plasmas

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] In weakly coupled thermal plasmas, the screened interaction between the plasma particles can be modeled by the standard Debye-H€ uckel potential obtained by the thermal Maxwellian distributions. In the space environment, however, plasmas are generally observed to possess a non-Maxwellian high-energy tail that can be well modeled by a generalized Lorentzian (or kappa) distribution function containing the spectral index j.…”