Electron-impact excitation of singly charged metal ions

Abstract

Fully relativistic distorted-wave theory has been applied to study the electron-impact excitation of the ns 1/2np 1/2 and ns 1/2 -np 3/2 resonance transitions of singly charged metal ions with one valence electron, viz., Mg + (n = 3), Ca + (n = 4), Zn + (n = 4), Cd + (n = 5), and Ba + (n = 6). Calculations are performed in the range of incident electron energies up to 300 eV for differential and integrated cross sections as well as for the linear polarization of the photon emissions following the decay of excited np 3/2 states. Results are compared with the available experimental data and previous nonrelativistic theoretical calculations. Moreover, analytic fits to our integrated cross sections are provided for potential applications in modeling plasma sources and environments.

Atomic Data for Zn Ii: Improving Spectral Diagnostics of Chemical Evolution in High-Redshift Galaxies

“…As already mentioned in Section 1.2, several elaborate studies on the Zn II ion electron-impact excitation were published;see Pindzola et al (1991), Zatsarinny & Bandurina (1999), and Sharma et al (2011). Becausetheir data are incompatible with our model due to a different atomic structure, a narrow energy range (as in Pindzola et al 1991, Zatsarinny & Bandurina 1999, and a different data type, when only excitation cross sections are plotted instead of collision rates, we cannot include those data inour data set or perform a comprehensive comparison with our data.…”

“…Scattering parameters for some transitions in this ion were determined by Pindzola et al (1991) andZatsarinny & Bandurina (1999) by employing R-matrix methods in the LS-coupling approximation. Sharma et al (2011) have applied a fully relativistic distorted-wave theory to study the electron-impact excitation of the ns-np resonance transitions in singly charged metal ions with one valence electron, including Zn + ions. Unfortunately, the abovementioned studies did not produce atomic data sets suitable for spectral modeling where the complete and consistent data are required.…”

Application of relativistic coupled-cluster theory to electron impact excitation of Mg+ in the plasma environment

“…The relativistic partial wave expansion, as described in our previous work [39], has been used for distorted wave functions F DW +(−) i,f of the projectile electron. For each partial wave, the large and small components of the continuum wave functions are obtained by solving the coupled Dirac equations using V d potential [39]. Thus, scattering amplitude given by Eq.…”

“…These transitions exist naturally in many astrophysical objects [37,38]. So far, a few theoretical and experimental investigations have been devoted to understand excitation processes in the plasma isolated Mg + ion [39][40][41][42][43][44]. However, such studies have never been carried out for plasma embedded Mg + .…”

“…The wave functions of the initial and final states of the Mg + ion are evaluated in the similar approach adopted to study ionization potential depressions (IPD) of the plasma embedded atomic systems [45,46]. Also, our previously reported RDW method [39] is extended further to calculate the wave function of the scattered electron in the vicinity of the plasma embedded atomic systems. We consider the Debye-Hückel screening potential model and solve the coupled Dirac equations using distortion potential, which is taken as the spherically averaged static potential of the target ion.…”