CORRELATION-POTENTIAL METHOD FOR NEGATIVE-IONS AND ELECTRON-SCATTERING

The relativistic correlation-potential method was used to calculate bi nding energies and fine-structure intervals for Pd, Ba, and Yb negativ e ions and to investigate low-energy electron scattering by Yb, Hg, an d Ra atoms. The results for the binding energies are the following: 54 0 meV for the 5s state of Pd-, 190 and 133 meV for the 6p1/2 and 6p3/2 states of Ba-, and 36 meV for the 6p1/2 state of the Yb-. A number of prominent p and d resonances are revealed in the scattering phase-shi ft calculations. These p or d resonances lead to a phenomenon of 100% polarization of the scattered electron beam at appropriate electron en ergy and scattering angle. A criterion is proposed to measure the stre ngth of the nonlocal correlation potential and to evaluate its ability to create a bound state: integral G(r',r)SIGMA(r,r')dr dr' > 1 is the necessary condition for the formation of a bound state. Here E is the correlation potential and G is the electron Green's function at zero energy.