  Unbiased molecular line surveys are a powerful tool for analyzing the
physical and chemical parameters of astronomical objects and are the only means
for obtaining a complete view of the molecular inventory for a given source.
The present work stands for the first such investigation of a photon-dominated
region. The first results of an ongoing millimeter-wave survey obtained towards
the Orion Bar are reported. The APEX telescope in combination with the APEX-2A
facility receiver was employed in this investigation. We derived the physical
parameters of the gas through LVG analyses of the methanol and formaldehyde
data. Information on the sulfur and deuterium chemistry of photon-dominated
regions is obtained from detections of several sulfur-bearing molecules and
DCN.
