Regge resonances in low-energy electron elastic cross sections for Ge, Sn and Pb atoms: manifestations of stable excited anions

Low-energy E < 2 eV electron elastic collisions with Ge, Sn and Pb atoms yield stable excited Ge-, Sn- and Pb- anions. The recent Regge-pole methodology is used with Thomas-Fermi type potential incorporating the crucial core-polarization interaction to calculate elastic total and Mulholland partial cross sections. For excited Ge- and Sn- anions the extracted binding energies from the unique characteristic sharp Regge resonances manifesting stable excited states formed during the collisions agree excellently with experimental values; for Pb- the prediction requires experimental verification. The calculated differential cross sections also yield the binding energies.