The chemistry of the massive outflow source G5.89-0.39 I. A 330-360 GHz molecular line survey

We have performed a 330 - 360 GHz molecular line survey of the molecular ga s associated with the ultracompact (UC) HII region G5.89-0.39. 142 lines or iginating from 19 species were detected and a further 6 lines that could no t be identified. Over 50% of the identified molecular lines are from sulphu r-bearing species, with SO2 land its isotopomer (SO2)-S-34) exhibiting the most lines. No emission from heavy organic molecules (e.g. dimethyl ether, ethanol, methyl formate) was detected. The lines can be divided into two ty pes by their profiles: narrow lines with no (or slight) wing emission which probe a molecular envelope surrounding the UC HII region and broad lines w ith considerable wings which may probe the gas in the bipolar molecular out flow associated with the UC HII region. We discuss the chemical models whic h may explain the features observed in the survey and outline the strategy for the chemical modelling of the evolution of the molecular gas, to be con sidered more quantatively in a following paper.