  In the framework of a non-relativistic quark model, the mass spectra of the
ground and excited states of doubly heavy $\Xi$ and $\Omega$ baryons are
calculated.
  We estimate the mass difference between the $ \Omega $ and corresponding $
\Xi $ baryons as $M_{\Omega}-M_{\Xi}\simeq178 $ MeV for all the states
containing $ cc,~bc $, or $ bb $ quarks.
  A simple form of the universal Isgur-Wise function, as the transition form
factor between the doubly heavy baryons, is introduced. Working in the
close-to-zero recoil limit, we investigate the $ b \rightarrow c $ semileptonic
decay widths and branching fractions of the doubly heavy baryons. The obtained
results are compared with other theoretical predictions.
