We perform a sensitive ( line confusion limited ) , single-side band spectral survey towards Orion KL with the IRAM 30m telescope , covering the following frequency ranges : 80-115.5 GHz , 130-178 GHz , and 197-281 GHz .
We detect more than 14 400 spectral features of which 10 040 have been identified up to date and attributed to 43 different molecules , including 148 isotopologues and lines from vibrationally excited states .
In this paper , we focus on the study of OCS , HCS ^ { + } , H _ { 2 } CS , CS , CCS , C _ { 3 } S , and their isotopologues .
In addition , we map the OCS J =18-17 line and complete complementary observations of several OCS lines at selected positions around Orion IRc2 ( the position selected for the survey ) .
We report the first detection of OCS \nu _ { 2 } = 1 and \nu _ { 3 } = 1 vibrationally excited states in space and the first detection of C _ { 3 } S in warm clouds .
Most of CCS , and almost all C _ { 3 } S , line emission arises from the hot core indicating an enhancement of their abundances in warm and dense gas .
Column densities and isotopic ratios have been calculated using a large velocity gradient ( LVG ) excitation and radiative transfer code ( for the low density gas components ) and a local thermal equilibrium ( LTE ) code ( appropriate for the warm and dense hot core component ) , which takes into account the different cloud components known to exist towards Orion KL , the extended ridge , compact ridge , plateau , and hot core .
The vibrational temperature derived from OCS \nu _ { 2 } = 1 and \nu _ { 3 } = 1 levels is \simeq 210 K , similar to the gas kinetic temperature in the hot core .
These OCS high energy levels are probably pumped by absorption of IR dust photons .
We derive an upper limit to the OC _ { 3 } S , H _ { 2 } CCS , HNCS , HOCS ^ { + } , and NCS column densities .
Finally , we discuss the D/H abundance ratio and infer the following isotopic abundances : ^ { 12 } C/ ^ { 13 } C = 45 \pm 20 , ^ { 32 } S/ ^ { 34 } S = 20 \pm 6 , ^ { 32 } S/ ^ { 33 } S = 75 \pm 29 , and ^ { 16 } O/ ^ { 18 } O = 250 \pm 135 .