15min:

Z. KISIEL, A. KRASNICKI, Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa, Poland; B. P. WINNEWISSER, M. WINNEWISSER, Department of Physics, The Ohio State University, Columbus, OH 43210.

The cyanamide molecule is one of the prototype systems for the study of the large-amplitude inversion motion at the nitrogen atom and it is also a known astrophysical species. The rotational and vibration-rotation spectrum of the parent species has already been studied in considerable detail.^, Information on the deuterated isotopologues has, hitherto, been limited to transitions measured at frequencies of less, or much less, than 60 GHz.

.2cm

Presently we report a detailed analysis of pure rotational and vibration-rotation transitions in the 0⁺-0^- inversion doublets for the two deuterated species. The analysis is based on a 118-650 GHz spectrum for D₂NCN and HDNCN recorded at rotational resolution, and an 8-360 cm^-1 spectrum of D₂NCN recorded with the Bruker IFS 120HR interferometer at resolution of 0.0025 cm^-1. The two spectra were assigned and analysed with the modified version of the AABS package for Assignment and Analysis of Broadband Spectra and the more extensive data set for D₂NCN contains well over 2000 lines with J\le80 and K_a\le15. The measured transition frequencies were fitted to within experimental accuracy with a unified scheme for fitting the inversion doublet transitions in H₂NCN, NHDCN and D₂NCN. The spectroscopic constants and information on the inversion potential determined from the spectra of the three isotopologues are compared and discussed.