Laboratory millimeter and submillimeter spectrum of HOC

The J = 1→2, 2→3, and 3→4 rotational transitions of the molecular ion HOC+ have been measured in the laboratory at frequencies from 178 to 358 GHz. The data should permit astronomers to confirm the recent possible sighting of the J = 1→0 transition of HOC+ in Sgr B2 at 89.5 GHz.