Microwave and millimetre wave spectra of diazirine-d2: Rotational and hyperfine structure analysis and molecular structure

Abstract

The rotational spectrum of diazirine-d2, [Formula: see text], has been recorded in the ranges 8–40 and 100–400 GHz. The hyperfine structure of the measured rotational lines has been analyzed. The analysis required the treatment of two pairs of equivalent nuclei, which is discussed in detail. The deduced deuterium nuclear-quadrupole coupling constants are[Formula: see text]The quadrupole coupling constants of the nitrogen nuclei[Formula: see text]are taken from the parent species, and the spin-rotation coupling constants are[Formula: see text]The rotational and centrifugal distortion constants have been obtained for the ground vibrational state from the analysis of the unperturbed line positions. The complete rs structure of diazirine has been determined using the rotational constants of all available isotopomers of diazirine. The internuclear distances are rs(C—N) = 148.13(24) pm, rs(C—H) = 108.03(29) pm, and rs(N—N) = 122.80(25) pm, and the bond angles are [Formula: see text] and [Formula: see text], with the HCH plane perpendicular to the NCN plane.