  Sensitivity of atomic transition frequencies to variation of the fine
structure constant $\alpha=e^2/\hbar c$ increases proportional to $Z^2$ where
$Z$ is the nuclear charge. Recently several lines of heavy ions Ge II, Sn II
and Pb II have been detected in quasar absorption spectra. We have performed
accurate many-body calculations of $\alpha^2$-dependence of transition
frequencies ($q$-coefficients) for these atoms and found an order of magnitude
increase in sensitivity in comparison with atomic transitions which were
previously used to search for temporal and spatial variation of $\alpha$ in
quasar absorption systems. An interesting feature in Pb II is highly non-linear
dependence on $\alpha^2$ due to the level pseudo-crossings.
