Dramatic resonances in low-energy electron scattering from Tm, Lu and Hf atoms: Manifestation of multiple excited anions

We predict the formation of multiple excited negative ionic states in low-energy 0 ≤ E ≤ 1.0 eV electron elastic scattering from Tm, Lu and Hf atoms. Their binding energies (BEs) are extracted from calculated elastic total and differential cross sections. Ramsauer-Townsend minima and shape resonances are also determined. The recent Regge-pole methodology has been used for the calculations. We conclude that the recently calculated BE value of 0.114 eV for the Hf− anion corresponds to an excited state.