Table A.1.
Assigned transitions for 
NCN, observed transition frequency (MHz), experimental uncertainty Unc. (MHz), residual O−C between observed frequency and that calculated from the final set of spectroscopic parameters, weight for blended lines, and source of line.
| J′ |  |
 |
 |
J″ |  |
 |
 |
Frequency | Unc. | O−C | Weight | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 19458.1 | 0.1 | −0.15777 | Tyler et al. (1972) | ||
| 2 | 0 | 2 | 0 | 1 | 0 | 1 | 0 | 38916.282 | 0.100 | 0.00717 | Brown et al. (1985) | ||
| 7 | 0 | 7 | 0 | 6 | 0 | 6 | 0 | 136194.32870 | 0.05000 | 0.00263 | Kraśnicki et al. (2011) | ||
| 8 | 0 | 8 | 0 | 7 | 0 | 7 | 0 | 155645.83281 | 0.05000 | −0.01287 | Kraśnicki et al. (2011) | ||
| 9 | 0 | 9 | 0 | 8 | 0 | 8 | 0 | 175095.43308 | 0.05000 | −0.00786 | Kraśnicki et al. (2011) | ||
| 21 | 6 | 15 | 1 | 20 | 6 | 14 | 1 | 407549.715 | 0.050 | 0.05275 | 0.5000 | Koeln | |
| 21 | 6 | 16 | 1 | 20 | 6 | 15 | 1 | 407549.715 | 0.050 | 0.05275 | 0.5000 | Koeln | |
| 25 | 6 | 19 | 1 | 24 | 6 | 18 | 1 | 485115.812 | 0.050 | 0.04584 | 0.5000 | Koeln | |
| 25 | 6 | 20 | 1 | 24 | 6 | 19 | 1 | 485115.812 | 0.050 | 0.04584 | 0.5000 | Koeln | |
| 26 | 6 | 20 | 1 | 25 | 6 | 19 | 1 | 504502.373 | 0.030 | −0.03347 | 0.5000 | Koeln | |
| 26 | 6 | 21 | 1 | 25 | 6 | 20 | 1 | 504502.373 | 0.030 | −0.03347 | 0.5000 | Koeln |
Notes. This table and those of other isotopologs are available in their entirety at the CDS. A portion is shown here for guidance regarding its form and content. The quantum number designators vt = 0 and 1 indicate the tunneling states 0+ and 0−, respectively.