Photoionization from the excitedpstates of the rare-gas atoms

A systematic quantitative estimation of the photoionization cross section from the excited $p$ states of the rare-gas atoms is carried out in a single-configuration calculation. Our calculation has shown that the photoionization from these excited states is quasihydrogenic in nature. At a fixed photoelectron energy, the cross section is found to decrease as the effective quantum number $n^{*}$ increases from state to state and to scale approximately as ${\left(n^{*}\right)}^{-3\mathrm{}}$. As the photon energy $\epsilon$ increases, the cross section decreases approximately as ${\epsilon }^{-3\mathrm{}}$. Our result is also found to compare favorably with the available experimental and theoretical data.