Atomic polarizability in negative-ion photodetachment

The influence of a strong atomic polarizability on photodetachment processes is isolated. In a model study of ${\mathrm{K}}^{-}$ photodetachment near the $4p_{\frac{1}{2}}$, $4p_{\frac{3}{2}}$ levels of K, the polarizability (${\alpha }_{4p}\simeq 600a_0^3$) is shown to cause a striking energy dependence of the parameters which determine the cross section. This study extends the effective range theory of O'Malley, Spruch, and Rosenberg to a broader energy range and to multichannel systems. An appendix provides a derivation of the polarization potential (and correction terms) starting from the electron-atom close-coupling equations, showing some new features.