Effect of polarization on photodetachment thresholds -: art. no. 052707

We have measured the near-threshold cross sections for the photodetachment of Li- into the e(-)(ks,d)-Li(2p(1/2)), e(-)(ks,d)-Li(3p), e(-)(kp)-Li(3s), and e(-)(kp)-Li(4s) continuum channels and the photodetachment of K- into the e(-)(ks,d)-K(4p(3/2)) continuum channel. The data was analyzed using both a top-of-barrier model and a modified effective range theory. Both approaches explicitly take into account the significant polarization potential in the final continuum channels. The study involving both experiment and theory enabled us to investigate the effect of the polarization on near-threshold photodetachment. Furthermore, since photodetachment and electron scattering are related in the half-collision concept, we were able to determine low-energy electron scattering quantities such as phase shifts, elastic cross sections, and s wave scattering lengths for electron scattering on excited Li and K atoms. The results allowed us to predict a virtual state in the e(-)(ks)-Li(3p) system.