C2N
Cyanomethylidyne, X 2Πr
Species tag 038502
Version2*
Date of EntryAug. 2003
ContributorH. S. P. Müller

The observed lines are from
(1) Y. Ohshima and Y. Endo, 1995, J. Mol. Spectrosc. 172, 225.
As in (1), effective A and γ values were kept fixed to values in
(2) M. Kakimoto and T. Kasuya, 1982, J. Mol. Spectrosc. 94, 380.
In addition, a was kept fixed to the value from (3) M. D. Allen, K. M. Evenson, D. A. Gillett, and J. M. Brown, 2000, J. Mol. Spectrosc. 201, 18.
With respect to the first entry from Aug. 2003, additional millimeter wave data were taken from (4) J. K. Anderson, D. T. Halfen, and L. M. Ziurys, 2015, J. Mol. Spectrosc. 307, 1.
The data in (4) are much better than the residuals suggest. There is likely a typographical error in one transition frequency (59067.070 MHz was used instead of 59067.007 MHz). The fit has been carried out employing Hund's case (b), as usual. Predictions for the lower spin-substate 2Π1/2 may be reliable up to 500 GHz, possibly higher. Predictions for the upper spin-substate 2Π1/2 should be viewed with great caution !
J + 1/2 = N correlates with 2Π1/2 for J + 1/2 ≤ 7 and with 2Π3/2 otherwise.
The dipole moment is from an ab initio calculation by
(3) R. Pd. and P. Chandra, 2001, J. Chem. Phys. 114 1589.
Since the calculated dipole moment differs considerably depending on the method and the basis set this value should be viewed with some caution. Many calculation yield values around 0.5 D.

Lines Listed574
Frequency / GHz< 1000
Max. J42
log STR0-8.3
log STR1-6.0
Isotope Corr.-0.0
Egy / cm 10.0
 µa / D0.425
 µb / D 
 µc / D 
 A / MHz 
 B / MHz11938.59
 C / MHz 
 Q(300.0)5748.1714
 Q(225.0)4192.3003
 Q(150.0)2651.4076
 Q(75.00)1159.1011
 Q(37.50)485.3470
 Q(18.75)212.3893
 Q(9.375)104.4865
detected in ISM/CSMyes


Database maintained by Holger S. P. Müller and Sven Thorwirth, programming by D. Roth and F. Schloeder