H13CCNC
Ethynyl isocyanide, isocyanoethyne, isocyanoacetylene; 13C on C3
Species tag 052543
Version1*
Date of EntryApr. 2024
ContributorH. S. P. Müller

The ground state fundamental rotational transition with 14N and 13C hyperfine splitting was published in
(1) M. Krüger, W. Stahl, and H. Dreizler, 1993, J. Mol. Spectrosc. 158, 298.
Two additional lower J transition frequencies were taken from astronomical observations by
(2) J. Cernicharo, B. Tercero, C. Cabezas, M. Agúndez, E. Roueff, R. Fuentetaja, N. Marcelino, and P. de Vicente, 2024, Astron. Astrophys. 682, L13.
The D value was kept fixed to the value of the main isopolog scaled by the square of the ratio of the B values. The 1H-13C nuclear spin-nuclear spin coupling parameter was kept fixed to the value in (1). The nuclear spin-rotation parameters were kept fixed to the values from a quantum-chemical calculation by
(3) H. S. P. Müller, 2020, unpublished.
The calculation may be accurate enough throughout, but some caution is advised.
14N and possibly 13C and 1H hyperfine splitting matter in some astronomical observations. Therefore, a separate hyperfine calculation is provided for J' ≤ 5 below 49 GHz. NOTE: The partition function does take into account the spin multiplicity of the 14N and 13C nuclei !
The experimental dipole moment of HCCNC was published by
(4) M. Krüger, H. Dreizler, D. Preugschat, and D. Lentz, 1991, Angew. Chem. 103, 1674.

Lines Listed20
Frequency / GHz< 200
Max. J20
log STR0-6.3
log STR1-2.5
Isotope Corr. 
Egy / cm–10.0
 µa / D 
 µb / D2.93
 µc / D 
 A / MHz 
 B / MHz4813.119
 C / MHz 
 Q(300.0)15593.7893
 Q(225.0)11695.4127
 Q(150.0)7797.6563
 Q(75.00)3900.5204
 Q(37.50)1952.1865
 Q(18.75)978.0813
 Q(9.375)491.0507
 Q(5.000)263.7859
 Q(2.725)145.6316
detected in ISM/CSMyes


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