  Adiabatic potential energy curves of the $^1\Sigma^+$ and $^1\Pi$ states of
the LiH molecule have been calculated. They correlate asymptotically to atomic
states, like 2s+1s, 2p+1s, 3s+1s, 3p+1s, 3d+1s, 4s+1s, 4p+1s and 4d+1s. Very
good agreement is found between our calculated spectroscopic parameters and
experimental ones. The dynamics of the rotational predissociation process of
the $1^1\Pi$ state has been studied by solving the time-dependent
Schr\"{o}dinger equation. The classical experiment of Velasco [Can. J. Phys.
{35}, 1204 (1957)] on dissociation in the $1^1\Pi$ state is explained in
detail.
