Knowledge Bank

Diazirine is the only stable three-membered ring isomer of diazomethane. It does not decompose in the gaseous phase, but can explode in the condensed states. The rotational spectrum of $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}C$- enriched diazirine and of the dideutero and monodeutero species have been measured in the microwave and millimeter wave region up to 250 GHz. The a-type R- and Q-branch transitions have been assigned for the ground vibrational state. A centrifugal distortion analysis has been carried out for all isotopic species using the A-reduced Watsonian. As in the case of the main isotopic species (1) the effects of nuclear quadrupolar and spin-rotational interactions lead to a characteristic hyperfine structure of the individual transitions which were analysed in order to determine the appropiate quadrupolar and spin rotational constants. The constants which will be reported reproduce the observed experimental spectra. The spectroscopic constants obtained by a least squares fit are currently being used in the analysis of the high resolution infrared spectra of the various isotopic species and for a reevaluation of the molecular structure.