Detection of H

Aims.The purpose of this study is to examine the prediction that the deuterated H$_3^+$ ion, H2D+, can be found exclusively in the coldest regions of molecular cloud cores. This is also a feasibility study for the detection of the ground-state line of ortho-H2D+ at 372 GHz with APEX. Methods.The $(1_{10} \rightarrow 1_{11})$ transition of H2D+ at 372 GHz was searched towards selected positions in the massive star forming cloud OriB