OBSERVATION OF DCO-MAGELLANIC-CLOUD( IN THE LARGE)

We report on the detection of DCO+ and, tentatively, DCN in their rota tional J=2-1 transitions towards the N159 region in the Large Magellan ic Cloud (LMC). These detections of deuterated molecules in an extraga lactic source complement those already published by Chin et al. (1996) . The resulting estimate of the HCO+/DCO+ abundance ratio is 120(-60)( +60) (total 2 sigma uncertainties). Assuming a Galactic D/H ratio for the LMC leads to an estimate of the kinetic temperature of the molecul ar gas and an upper limit to the fractional electron abundance of 10-2 7 K and a fewx10(-5), respectively. The temperature estimate is in acc ordance with excitation calculations using a number of other molecules . The HCO+/DCO+ abundance ratio in N159 is a factor of a few higher th an in cores of Galactic molecular clouds. This is probably due to a so mewhat higher gas temperature and possibly a considerably higher elect ron abundance in N159. The estimated HCN/DCN abundance ratio is 60(-35 )(+50) (total 2 sigma uncertainties).