  (Abridged) Bright-rimmed clouds (BRCs) are isolated molecular clouds located
on the edges of evolved HII regions where star formation is thought may have
been triggered. In this paper we investigate the current level of star
formation within a sample of BRCs and evaluate to what extent star formation
may have been induced. We present the results of a programme of
position-switched CO observations towards 45 southern BRCs. The 12CO, 13CO and
C18O (J=1-0) were simultaneously observed using the 22m Mopra telescope. We
complement these observations with archival mid-IR submm and radio data.
Analysis of the CO, mid-IR and radio data result in the clouds being divided
into three distinct groups. We refer to these groups as spontaneous, triggered,
and zapped clouds, respectively. Comparing the physical parameters of
spontaneous and triggered samples we find striking differences in luminosity,
surface temperature and column density with all three quantities significantly
enhanced for the clouds considered to have been triggered. Furthermore, we find
strong evidence for star formation within the triggered sample by way of
methanol and H_2O masers, embedded mid-IR point sources and CO wings, however,
we find evidence of ongoing star formation within only two of the spontaneous
sample. We have used CO, mid-IR and radio data to identify 24 of the 45
southern BRCs that are undergoing a strong interaction with their HII region.
We can therefore exclude ~50% from future studies. 14 of the 24 interacting
BRCs are found to be associated with embedded mid-IR point sources and we find
strong evidence of that these clouds are forming stars. The absence of
mid-infrared sources towards the remaining ten clouds leads us to conclude that
these represent an earlier evolutionary stage of star formation.
