The tentative identification of silylidyne, SiH, toward Orion KL
was reported by
P. Schilke, D. J. Benford, T. R. Hunter, D. C. Lis, and T. G. Philips,
A Line Survey of Orion-KL from 607 to 725 GHz
Astrophys. J. Suppl. Ser. 132, 281364 (2001).
The two λ components of the J = 1.5 0.5 transition pertaining to the energetically lower lying Π1/2 spin-state near 624.9 and 627.7 GHz were detected. However, they were at least partially overlapped. As the source is rather line rich, the detection was viewed as tentative.