Abstract
In this paper we examine the treatment of the Fermi shift in the paper by M. H. Choudhury, Phys. Rev. 186, 66 (1969). Some difficulties are pointed out which render Choudhury's results to be of doubtful value. It is seen that starting from Choudhury's Hamiltonian one may recover an equation considered earlier by Mittleman for studying the Fermi-shift phenomenon. Finally, the Mittleman result is employed to make new estimates for the electron-neutral-atom scattering lengths.