THE VIBRONIC ABSORPTION SPECTRA OF a-DIAZIRINE, $d_{1}$ DIAZIRINE, $d_{2}$-DIAZIRINE AND $N^{15}$-DIAZIRINE.

Author Institution: Physical Sciences Laboratory, Directorate of Research and DevelopmentElectronic absorption spectra of n-diazirine, $d_{1}$-diazirine, $d_{2}$-diazirine and $N^{15}$-diazirine have been obtained. The 0-0 bands appear at $30970 cm^{-1}, 31015 cm^{-1}, 31061 cm^{-1}$, and $30976 cm^{-1}$, respectively. The spectra are very diffuse and rotational structure was not observed. CN (ring) vibrations are the prominent bands observed in the excited state. Because of the strong progression of the $B_{2}$ species appearing in combination with the $A_{2}$ species, the electronic transition is probably a $B_{1} \leftarrow A_{1}$ transition