Photoionization Yield Spectra below the Atomic Ionization Limit in Xenon

Photocurrent yield and absorption spectra for xenon were measured as functions of pressure (p<~1×10⁵ Pa) between {~}11.0 and 11.8 eV. With a pressure-independent yield function Y(hν) the photocurrent spectra can be calculated from the absorption spectra with the assumption of a "dead layer" at the surface of the LiF window. Y(hν) is roughly proportional to the number of atomic transitions with excitation energies between 11.10 eV and hν. This behavior can be explained with a simple statistical model for the decay of the Rydberg states.