  Three-body charge transfer reactions with Coulomb interaction in the final
state are considered in the framework of coordinate-space integro-differential
Faddeev-Hahn-type equations within two- and six-state close coupling
approximations. The method is employed to study direct muon transfer in
low-energy collisions of the muonic hydrogen H$_\mu$ by helium (He$^{++}$) and
lithium (Li$^{+++}$) nuclei. The experimentally observed isotopic dependence is
reproduced.
