Positron annihilation in ionic media and positron optical model

To describe positron movement in quasiatomic positron + anion systems, formed in ionic media, it is proposed to use potential Veff(r)=Zeff/r2 - η/r, where Zeff is the nuclear effective charge, η is the anion effective charge. It is shown that the positron wave function of the ground state of the quasiatomic positron + anion system in the given potential field is Ψχ(r)=1/√4π x Anχ x rχ x e-αr. Hence, it is confirmed that the trial variation positron wave function Ψ(r) 1/√4π x A x r x e-αr for the potentials Veff=∞ at r=0 and Veff=-η/r at r>0, belonging to the Ψχ(r) functions class, is chosen correctly. Annihilation photon angular distribution (APAD) curves, half-widths of APAD curves Gns,p and positron lifetimes τns,p are calculated using Ψχ(r) wave functions and Ψns,p(r) Slater wave functions of electrons anions