  The theory of collisional depolarization of spectral lines by atomic hydrogen
(Derouich et al. \cite{derouich1}) is extended to $d$ $(l$=2) atomic levels.
Depolarization rates, polarization and population transfer rates are calculated
and results are given as a function of the temperature. Cross sections as a
function of the effective quantum number for a relative velocity of 10
$\textrm{km s}^{-1}$ are also given together with velocity exponents $\lambda$,
if \textbf{they exist}, on the assumption that the cross section varies with
velocity as $v^{-\lambda}$. A discussion of our results is presented.
