Symmetric-charge-transfer cross sections for gadolinium in the energy range 10-1000 eV.

Abstract

The cross section of symmetric charge transfer between Gd and ${\mathrm{Gd}}^{+}$ as a function of impact energy (velocity) in the range of 10--1000 eV (3.5\ifmmode\times\else\texttimes\fi{}${10}^{5}$--3.5\ifmmode\times\else\texttimes\fi{}${10}^{6}$ cm/sec) was successfully obtained by a crossed-beam technique, which featured a pulsed ion beam produced by laser photoionization in an atomic gas beam. The absolute values and the impact-energy dependence of the cross sections were obtained from the attenuation rate of the primary ions in the atomic gas and the ratio of the detected charge transferred ions to the primary ions, respectively. The cross sections obtained are larger than those of other elements studied in the past, and the impact-velocity--cross-section curve could be fitted with that obtained from the superposition of the resonant and capture-type probabilities resulting in charge transfer, assuming that the capture-type cross section is inversely proportional to the impact velocity.