  We have used a combined dynamic scanning tunneling and atomic force
microscope to study the organisation of weakly bound adsorbed molecules on a
graphite substrate. Specifically we have acquired images of islands of the
perylene derivative molecules. These weakly bound molecules may be imaged in
dynamic STM, in which the probe is oscillated above the surface. We show that
molecular resolution may be readily attained and that a similar mode of imaging
may be realised using conventional STM arrangement. We also show, using
tunnelling spectroscopy, the presence of an energy gap for the adsorbed
molecules confirming a weak molecule-substrate interaction.
