Elastic positron versus elastic electron scattering off Mn

Earlier [1, 2], we demonstrated the specific multielectron features of elastic electron scattering by Mn atom due to its 3d⁵ semifilled subshell. We now study [3] to what extent the elastic scattering of positrons by Mn can differ from the scattering of electrons by this atom. This is all the more interesting and important, since today little is known about the elastic scattering of positrons by atoms possessing a multielectron half-filled subshell in the ground state, as far we know. The problem is theoretically complex. This due to both the need to accurately take into account the correlation effects affecting the scattering of the projectile by such atoms, and accounting for the formation of virtual Ps in the scattering of positrons by the atom. In the present study, we fairly accurately account for correlation effects using the Dyson formalism for both the electron and positron Green’s function in the framework of the RPAE theory. As for the formation of virtual Ps in the e⁺ + Mn scattering, we take into account the latter in a reasonable, albeit simplified, approximation, as in [4]. One of the key findings of this study is that the e⁺ + Mn and e⁻ + Mn elastic scattering cross sections follow different paths at  lower energies, with the result that the low-energy e⁺ + Mn cross section domiantes the e⁻ + Mn cross section to the degree not previously observed or predicted for other atoms such as alkali and noble atoms. [1] V. K. Dolmatov 2017 Phys. Rev. A 96 052704. [2]  V. K. Dolmatov, M. Ya. Amusia, and L. V. Chernysheva 2013 Phys. Rev. A 88 042706. [3] M. Ya. Amusia, V. K. Dolmatov, and L. V. Chernysheva 2021 J. Phys. B (Accepted manuscript). [4] M. Ya. Amusia et al., 2003 JETP 97 34.