Effect of charge transfer on elastic scattering of electron from Ar@C60: Dirac partial wave calculation

Elastic electron scattering from C60 and Ar@C60 is studied using the Dirac partial wave methodology. The endohedral environment is approximated as an atom trapped in an attractive spherically symmetric potential employing two model potentials: (A) hard annular square well (ASW) and (B) diffused Gaussian annular square well (GASW). The objective of the present work is twofold; the first focus is to study the effect of charge transfer from encaged Ar to C60 shell on e-Ar@C60 scattering. Various well depths for model potentials are employed in order to investigate charge transfer and its impact on scattering dynamics. The present work validates the earlier assumption of Dolmatov et al. (Phys Rev A 91: 062703, 2015) that if the endohedral atom is compact, C60 shields the atom from incoming electron, giving identical e-C60 and e-Ar@C60 total scattering cross section. However, the differential cross section is seen as sensitive to the presence of endohedral atom. The second objective is to contrast e-C60 and e-Ar@C60 scattering employing compact and diffused model potentials. Importantly, the question regarding the suitability of compact Vs diffuse model potential is addressed by comparing the e-C60 scattering attributes with that from experiment and available ab initio calculations.