Microwave spectrum of the HNCN radical in theXtilde;thinsp;2Alsquo;ground electronic state

摘要

The rotational spectral lines of the HNCN radical are observed in the millimeterhyphen;wave and submillimeterhyphen;wave regions. The radical is produced in a glowhyphen;discharge plasma of a gaseous mixture of CH4and N2at the room temperature. Rotational constants, centrifugal distortion constants, and spinndash;rotation interaction constants with their centrifugal distortion corrections are precisely determined from observed frequencies of 43ahyphen;typeRbranch transitions withN=12minus;11 toN=18minus;17 andKa=0 toKa=3. From the observed spinndash;rotation interaction constant, egr;aa, the energy of theAtilde;thinsp;2Arsquo;electronic state is estimated to be 12thinsp;000 cmminus;1, which is comparable to the energy of the corresponding electronic state (Atilde;thinsp;2A1) for the NH2radical. A preliminary radioastronomical search for the HNCN radical is carried out toward the Galactic center without success. copy;1994 American Institute of Physics.