We propose to observe  high J rotational and  rot-vib lines of
  sulfur-bearing  molecules  in  active  star-forming  molecular
  clouds.  Chemical reactions leading to the formation of sulfur
  compounds are highly endothermic and several observational and
  theoretical   studies  have   suggested  that  sulfur  bearing
  molecular  species  may  be  unique  tracers  of  warm  gas in
  interstellar  shocks  and/or photon-dominated regions in dense
  molecular clouds in star-forming regions.

Our observations  will provide  new information  about the physical
conditions  in the  shocks  and photon-dominated  regions (PDRs) in
which  sulfur  species  become  abundant.  By comparison with model
calculations of excitation and chemical  processes  we will be able
to determine the density, column density, temperature and abundance
of the sulfur-bearing species.

The observation of sulfur compound lines is not part of the central
central program projects. The proposed observations will complement
the central program  (MPEWARM  Drapatz et al.)  data of shocked and
photon dominated regions.