Notes. ^(a) c-C₃H₂ peak intensities and line widths taken from the south peak where there is no line confusion. ^(b) Blended 10_0,10 –9_1,9 and 10_1,10 –9_0,9 transitions of c-C₃ H₂. ^(c) Blended 9_1,8 –8_2,7 and 9_2,8 –8_1,7 transitions of c-C₃ H₂. ^(d) 1σ noise level of N₂D⁺ and N₂H⁺ in 0.02 km s⁻¹ channel.

References. All rest frequencies were taken from the Cologne Database for Molecular Spectroscopy (CDMS; Endres et al. 2016). The c-C₃ H₂ entry was based on Bogey et al. (1987) with transition frequencies important for our survey from Bogey et al. (1986) and from Spezzano et al. (2012). The CCH entry is based on Padovani et al. (2009) with additional important data from Müller et al. (2000) and Sastry et al. (1981). The DCO⁺ and N₂H⁺ entries are based on Caselli & Dore (2005) and on Cazzoli et al. (2012), respectively. Information on the N₂D⁺ rest frequency was taken from Pagani et al. (2009a).