HNCNH
Diiminomethan, carbodiimide
Species tag 042506
Version1*
Date of EntrySep. 2006
ContributorH. S. P. Müller

Diiminomethan is the higher energy isomer of cyanamine, H2NCN. Relative intensity measurements suggest the difference to be about 15 KJ/mol or 1700 K. These measurements as well as a substantional number transitions were reported in
(1) M. Birk, M. Winnewisser, and E. A. Cohen, 1989, J. Mol. Spectrosc. 136, 402.
Further transition frequencies near 1.1 THz come from
(2) W. Jabs, M. Winnewisser, S. P. Belov, T. Klaus, and G. Winnewisser, 1997, Chem. Phys. 225, 77.
Further lines were published in
(3) V. Wagener, M. Winnewisser, and M. Bellini, 1995, J. Mol. Spectrosc. 170, 323.
However, transitions near 2.5 THz reported in (1) and (3) deviate systematically by slightly more than 1 MHz; the latter is the combined uncertainty for each line. Therefore, data from (3) were not used in the fit. As a consequence, predictions above Ka" = 1 should be viewed with some caution. Because of the fairly large body of transitions measured by FT-FIR, the predictions should not deviate by much more than 5 MHz.
Apparently the tunneling of the HNCNH molecule should be described by four states. The measured data, however, can only provide information on two states – even theoretically. Therefore, the final fits have been carried out by employing two tunneling states only. A 5 : 7 spin-statistical weight ratio was considered in the predictions.
The dipole moment was reported in (1).

Lines Listed2895
Frequency / GHz< 3600
Max. J65
log STR0-7.0
log STR1-5.0
Isotope Corr.-0.0
Egy / cm–10.0
 µa / D 
 µb / D1.9
 µc / D 
 A / MHz379244.4
 B / MHz10366.941
 C / MHz10366.089
 Q(300.0)52401.4128
 Q(225.0)33994.0719
 Q(150.0)18484.0985
 Q(75.00)6532.4747
 Q(37.50)2312.7708
 Q(18.75)820.9379
 Q(9.375)296.2973
detected in ISM/CSMyes


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