The first detection of l-C3H+ was reported, disputed, and confirmed in
2012-2014. In 2012 Pety et al. reported the
observation of l-C3H+ toward the
using the IRAM 30 m telescope. Six
lines in the survey were assigned to l-C3H+. In 2013 the detection was disputed by
Huang et al. on the basis of very accurate
quantum chemical calculations of the rotational constants of l-C3H+, suggesting that
the line assigments were incorrect. But in 2014
Brünken et al. remeasured the rotational
spectrum of l-C3H+ and found that the orginal assignments of Pety et al. were
correct. Subsequently, Guzmán et al.
improved upon the spatial resolution of the initial detection in the Horsehead PDR.