Low-lying 3P0 and 3Se states of Rb-, Cs-, and Fr- -: art. no. 022722

Our Dirac R-matrix calculations suggest that none of the heavy alkali-metal negative ions, Rb, Cs, and Fr, has an excited bound stare. Their lowest excited state appears to be a multiplet of P-3(J)0-shape resonances, the J = 1 component of which was recently observed in photodetachment experiments on Cs-. We analyze these P-3(J)0 and the S-3(e) excited negative ion states in partial and converged total scattering cross sections for slow electrons with incident kinetic energies below 120 meV. Our results are in excellent agreement with available experimental data. We also propose a new value for the electron affinity of Pr, provide the scattering length for electronic collisions with Rb, Cs, and Fr, and discuss the nuclear charge dependence of relativistic effects in the resonance profiles.