  Mechanisms of nonradiative recombination of electron-hole complexes in
Cd(Mn)Se/Zn(Mn)Se quantum dots accompanied by interconfigurational excitations
of Mn$^{2+}$ ions are analyzed within the framework of single electron model of
deep {\it 3d}-levels in semiconductors. In addition to the mechanisms caused by
Coulomb and exchange interactions, which are related because of the Pauli
principle, another mechanism due to {\it sp-d} mixing is considered. It is
shown that the Coulomb mechanism reduces to long-range dipole-dipole energy
transfer from photoexcited quantum dots to Mn$^{2+}$ ions. The recombination
due to the Coulomb mechanism is allowed for any states of Mn$^{2+}$ ions and
{\it e-h} complexes. In contrast, short-range exchange and ${\it sp-d}$
recombinations are subject to spin selection rules, which are the result of
strong {\it lh-hh} splitting of hole states in quantum dots. Estimates show
that efficiency of the {\it sp-d} mechanism can considerably exceed that of the
Coulomb mechanism. The phonon-assisted recombination and processes involving
upper excited states of Mn$^{2+}$ ions are studied. The increase in PL
intensity of an ensemble of quantum dots in a magnetic field perpendicular to
the sample growth plane observed earlier is analyzed as a possible
manifestation of the spin-dependent recombination.
