  In this paper we report calculations of potential energy curves in the $1.2
a.u.\le R\le100 a.u.$ range at Multireference Configuration Interaction (MRCI)
level for doubly excited states of the H$_2$ molecule. We have focused on the
$Q_2$ states which lie between the second and third ionization thresholds of
H$_2^+$ molecular ion, i.e., $^2\Sigma_u^+$ state in which lie the H(2l) +
H(2l') dissociation channels. The MRCI approach allowed us to successfully
identify for the first time the molecular state which dissociates into hydrogen
atoms at 2s state. Further, Generalized Oscillator Strength as a function of
transferred momentum for three doubly excited states is also presented.
  (Some figures in this article are in colour only in the electronic version)
