Cross sections and equilibrium charge fractions when D$sub 2$$sup +$ is incident on Cs vapor

The total cross section for charge exchange or breakup when ${\mathrm{D}}_{2}^{+}$ is incident on Cs has been measured in the energy range 3.0-23 keV. The cross section has a value of (1362 \ifmmode\pm\else\textpm\fi{} 80) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}17}$ ${\mathrm{cm}}^{2}$ at 3 keV and falls rapidly with increasing energy, reaching a value of (594 \ifmmode\pm\else\textpm\fi{} 40) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}17}$ ${\mathrm{cm}}^{2}$ at 23 keV. The equilibrium fraction of ${\mathrm{D}}^{\ensuremath{-}}$ obtained when ${\mathrm{D}}_{2}^{+}$ is incident on Cs has also been measured. The equilibrium fraction of ${\mathrm{D}}^{\ensuremath{-}}$ is (10.5 \ifmmode\pm\else\textpm\fi{} 2.0)% at 3 keV, (7.3 \ifmmode\pm\else\textpm\fi{} 1.6)% at 5 keV, (3.4 \ifmmode\pm\else\textpm\fi{} 0.7)% at 11.5 keV, (2.0 \ifmmode\pm\else\textpm\fi{} 0.4)% at 17.3 keV, and (1.5 \ifmmode\pm\else\textpm\fi{} 0.3)% at 23 keV. The equilibrium fraction of ${\mathrm{D}}^{\ensuremath{-}}$ obtained when ${\mathrm{D}}_{2}^{+}$ is incident on Cs at an energy $E$ is shown experimentally to be the same as the equilibrium fraction of ${\mathrm{D}}^{\ensuremath{-}}$ obtained when ${\mathrm{D}}^{+}$ is incident on Cs at an energy $\frac{1}{2}E$. The angular distribution of the reaction products when ${\mathrm{D}}_{2}^{+}$ ions are incident on Cs includes appreciable scattering into angles which are larger than 1\ifmmode^\circ\else\textdegree\fi{}. An explanation of these large scattering angles is offered.