Knowledge Bank

The rotational and rovibrational spectra of isocyanogen, CNCN, have been observed for the first time. In the region from 10 to 40 GHz the rotational transitions of the ground and four excited vibrational states as well as the ground state transitions of four isotopic species in natural abundance have been measured by FT-MW spectroscopy. The measurements were also extended to the MMW and SMMW regions. The rotational analysis and the analysis of the observed complex nuclear quadrupole hyperfine structure of the individual rotational transitions are in progress. From the obtained preliminary rotational constants we have determined the structure of the non-centrosymmetric molecule CNCN: $r(C\equiv N-)=117.5pm,r(N\equiv C)=131.4pm$ and $r(-C\equiv N)=116.0pm$. The vibrational fundamentals were observed by high resolution FT-IR spectroscopy using the Bruker IFS 120 HR. The band centers determined so far are located at $\nu ¯1=2302.00cm-1,\nu ¯2=2059.73cm-1,\nu ¯3\approx =975cm-1,\nu ¯4\approx 470cm-1$ and $\nu ¯3=194.753cm-1$. Further measurements of these bands and their respective analysis will be reported at the meeting.