Electron momentum spectroscopy of xenon: A detailed analysis

Accurate measurements of the 1000-eV noncoplanar symmetric (e,2e) reaction on xenon are reported. Cross-section calculations are carried out with the use of both the plane-wave and distorted-wave impulse approximations. The distorted-wave impulse approximation accurately describes both the 5$p^{\mathrm{-}1}$ and 5$s^{\mathrm{-}1}$ angular correlations and their relative cross sections. It also describes accurately the 5$p_{3/2}^{\mathrm{-}1}$:5$p_{1/2}^{\mathrm{-}1}$ branching ratios if Dirac-Fock target wave functions are used. The branching ratios show the inadequacy of Hartree-Fock wave functions for xenon. The plane-wave impulse-approximation overestimates the 5$s^{\mathrm{-}1}$ cross section relative to the 5$p^{\mathrm{-}1}$ and underestimates the cross section at large angles. The 5$s^{\mathrm{-}1}$ spectroscopic factors are assigned up to a separation energy of 45 eV, and the distorted-wave impulse-approximation calculation verifies that all the 5$s^{\mathrm{-}1}$ strength has been found. The spectroscopic factors for the 5$s^{\mathrm{-}1}$ manifold are obtained at 1000 and 1200 eV at a number of angles and are found to be independent of incident energy and ion recoil momentum. The spectroscopic factor for the lowest 5$s^{\mathrm{-}1}$ transition at 23.4 eV is 0.37±0.01, whereas that for the ground-state 5$p^{\mathrm{-}1}$ transition is greater than or equal to 0.98.