  We present recent results from our radial velocity (RV) studies of rapidly
oscillating Ap (roAp) stars. Our measurements reveal that the pulsational
amplitude of these stars depends on the spectral region that is examined. For
one star, gamma Equ, the pulsational RV amplitude depends on both line strength
and atomic species. The elemental difference is most likely related to the
abundance patches on the surface of these stars. The line strength difference
is interpreted as arising form a height effect in the atmosphere. Ultimately,
these measurements may provide valuable diagnostics of the atmospheres of these
stars.
