  Spectrum of $^7$Li and elastic scattering reaction $^4$He($^3$H, $^3$H)$^4$He
are studied using the unified description of the Gamow shell model in the
coupled-channel formulation (GSMCC). The reaction channels are constructed
using the cluster expansion with the two mass partitions [$^4$He + $^3$H],
[$^6$Li + n].
