Knowledge Bank

The high resolution microwave spectrum of the stable radical bis-trifluoromethyl nitroxide, $(CF3)2NO$, has been observed in the region from 18-26.5 GHz. The rotational constants determined by calculation of the hypothetical unsplit rotational transitions and use of the Kirchoff NBS fitting $program1$ are: $A=2256.94,B=1056.08$, and $C=971.515MHz$. Using the irreducible tensor technique to evaluate the nonvanishing matrix elements, the analysis of the hyperfine structure of 9 separate transitions yielded spin-rotation coupling constants of $Eaa=-35.98,Ebb=-11.21$, and $Ecc=0.30MHz$ and hyperfine interaction constants of $Taa=-183.74,Tbb=-177.77,Tcc=361.51$, and $aF=22.8MHz$. A preliminary structural fit of the rotational constants shows that the bond lengths are close to those of similar compounds and indicates that the angle which measures the deviation of the 0 atom from the CNC plane is 0''. Details regarding the calculation of the hyperfine interaction and the structural parameters obtained will be discussed.