  The triton energy spectra of the charge-exchange $^{12}$C($^3$He,t) reaction
at 2 GeV beam energy are analyzed in the quasi-elastic nucleon knock-out
region. Considering that this region is mainly populated by the charge-exchange
of a proton in $^3$He with a neutron in the target nucleus and the final proton
going in the continuum, the cross-sections are written in the distorted-wave
impulse approximation. The t-matrix for the elementary exchange process is
constructed in the DWBA, using one pion- plus rho-exchange potential for the
spin-isospin nucleon- nucleon potential. This t-matrix reproduces the
experimental data on the elementary pn $\rightarrow $np process. The calculated
cross-sections for the $^{12}$C($^3$He,t) reaction at $2^o$ to $7^o$ triton
emission angle are compared with the corresponding experimental data, and are
found in reasonable overall accord.
