  Although surveys of infall motions in dense cores have been carried out for
years, few surveys have focused on mapping infall across cores using multiple
spectral line observations. To fill this gap, we present IRAM 30-m Telescope
maps of N2H+(1-0), DCO+(2-1), DCO+(3-2), and HCO+(3-2) emission towards two
prestellar cores (L492 and L694-2) and one protostellar core (L1521F). We find
that the measured infall velocity varies with position across each core and
choice of molecular line, likely as a result of radial variations in core
chemistry and dynamics. Line-of-sight infall speeds estimated from DCO+(2-1)
line profiles can decrease by 40-50 m/s when observing at a radial offset >=
0.04 pc from the core's dust continuum emission peak. Median infall speeds
calculated from all observed positions across a core can also vary by as much
as 65 m/s depending on the transition. These results show that while
single-pointing, single-transition surveys of core infall velocities may be
good indicators of whether a core is either contracting or expanding, the
magnitude of the velocities they measure are significantly impacted by the
choice of molecular line, proximity to the core center, and core evolutionary
state.
