Elastic electron scattering from Ar@C₆₀^z+: Dirac partial wave analysis

Photoionization spectra of A@C₆₀^z- introduces interesting features like Coulomb confinement resonances (CCR); a new variety of confinement resonances caused due to Coulomb barrier, whereas for cationic states merely a shift of ionization potential towards higher threshold is noticed¹. It is imperative to search for the electron scattering dynamics with such targets, which is not elaborately explored so far compared to that of neutral targets^2-3. The present work accounts for a detailed analysis of scattering parameters using Dirac partial wave analysis, emphasizing the role of encaged Ar atom and C₆₀^z+ cage in electron scattering from Ar@C₆₀^z+ for z=1 and 6. Two contrasting types of model C₆₀ potential with charged-shell potential are employed¹. The role of Coulomb field and short-range interactions on scattering dynamics is elucidated through an analysis of the non-Coulomb scattering phase shifts. Differential cross section shows (DCS) oscillatory structures owing to interference of Coulomb and short-range interactions at the intermediate angles. DCS at backward angles comprises of interferences arising due to internal structure of the target (short-range field)⁴ and Coulomb field dominates near the forward angles. A piecewise scattering approximation can be proposed for charged endohedral scattering, similar to the way it was introduced earlier in electron scattering with endohedral target². Total cross section shows solely the dominance of Coulomb field; irrespective of the size of target. Target polarization is found significant for smaller z and at low energy.

¹V. K. Dolmatov, and S. T. Manson, Phys. Rev. A 73, 013201 (2006).

²V. K. Dolmatov, C. Bayens, M. B. Cooper, and M. E. Hunter, Phys. Rev. A 91, 062703 (2015).

³C. Winstead, and V. McKoy, Phys. Rev. A 73, 012711 (2006).

⁴I. D. Williams, Rep. Prog. Phys. 62, 1431 (1999).