Total charge-transfer cross sections forH+,H2+,H3+,He+,N+,N2+,Ne+,Ar+,Kr+, andXe+incident on Cs

Abstract

The total cross section for electron capture has been measured for ${\mathrm{H}}^{+}$, ${\mathrm{He}}^{+}$, ${\mathrm{N}}^{+}$, ${\mathrm{Ne}}^{+}$, ${\mathrm{Ar}}^{+}$, ${\mathrm{Kr}}^{+}$, and ${\mathrm{Xe}}^{+}$ incident on a Cs vapor target. The energy range investigated was 40-120 keV for incident protons, 30-140 keV for incident ${\mathrm{N}}^{+}$, and 20-200 keV for the incident noble-gas ions. Also measured was the total attenuation cross section for ${\mathrm{H}}_{2}^{+}$, ${\mathrm{H}}_{3}^{+}$, and ${\mathrm{N}}_{2}^{+}$ incident on Cs in the energy range 30-160 keV. These attenuation cross sections result from either electron capture or breakup of the incident molecular ion. At velocities below 5\ifmmode\times\else\texttimes\fi{}${10}^{5}$ m/sec, the various cross sections are different both in magnitude and velocity dependence. In the velocity range (0.5-1.5)\ifmmode\times\else\texttimes\fi{}${10}^{6}$ m/sec, the cross sections for the various incident ions are almost completely independent of the identity of the incident ion. At velocities above 1.5\ifmmode\times\else\texttimes\fi{}${10}^{6}$ m/sec, the individual cross sections are different from one another again. The behavior of the measured cross sections is discussed in terms of a theoretical model for near-resonant charge transfer.