GEOMETRY EFFECTS ON THE (E, 2E) TRIPLE DIFFERENTIAL CROSS SECTIONS OF LI+,NA+, AND K+

The three-body distorted-wave Born and impulse approximations with spin-averaged static exchange potential have been used to calculate the electron-impact triple-differential ionization cross sections (TDCS's) of ${\mathrm{Li}}^{+},$ ${\mathrm{Na}}^{+},$ and ${\mathrm{K}}^{+}$ ions in different geometries and kinematics. In coplanar geometry at high incident energy (g500 eV) and scattering angle $\ensuremath{\sim}10\ifmmode^\circ\else\textdegree\fi{},$ both recoil and binary peaks split into two in case of p-electron targets $({\mathrm{Na}}^{+}$ and ${\mathrm{K}}^{+}$ ions). In noncoplanar geometry a strong interference resulting in a dip in TDCS's has been noticed. In the perpendicular plane geometry, single- and double-scattering mechanisms together produce an oscillatory structure in the TDCS's of a ${\mathrm{K}}^{+}$ ion. The values of the binary-to-recoil peak ratio for specific values of the momentum transfer have been determined to understand collision dynamics.