  Absolute cross sections for charge-exchange, ionization and excitation in
Na$% ^{+}-$Ne and Na$^{+}-$Ar collisions were measured in the ion energy range
$% 0.5-10$ keV using a refined version of a capacitor method, and collision and
optical spectroscopy methods simultaneously in the same experimental set-up.
Ionization cross sections for Ne$^{+}-$Na and Ar$^{+}-$Na collisions are
measured at the energies of $2-14$ keV using a crossed-beam spectroscopy
method. The experimental data and the schematic correlation diagrams are used
to analyze and determine the mechanisms for these processes. For the
charge-exchange process in Na$^{+}$ $-$Ar collisions two nonadiabatic regions
are revealed and mechanisms responsible for these regions are explained.
Structural peculiarity on the excitation function for the resonance lines of
argon atoms in Na$^{+}$ $-$Ar collisions are observed and the possible
mechanisms of this phenomenon are explored. The measured ionization cross
sections for Na$^{+}-$Ne and Ne$^{+}-$Na collisions in conjunction with the
Landau-Zener formula are used to determine the coupling matrix element and
transition probability in a region of pseudo-crossing of the potential curves.
