  We consider a potential scattering of Bose-Hubbard dimer in 1D optical
lattice. A numerical approach based on effective non-Hermitian Hamiltonian has
been developed for solving the scattering problem. It allows to compute the
tunneling and dissociation probabilities for arbitrary shape of the potential
barrier and arbitrary kinetic energy of the dimer. The developed approach has
been used to address the problem of two-particle decay out of a trap. In
particular, it is shown that the presence of dissociation channels
significantly decreases non-escape probability due to single-particle escape to
those channels.
