Detection of the Millimeter Wave Spectrum of Hydrogen Isocyanide, HNC1,2

Abstract

The rotational spectra of three isotopic species of HNC have been observed in the millimeter wave region. In the case of the parent species, H14N12C, our measurement of the J = 1←0 transition unequivocally confirms the assignment of the U90.7 interstellar line to HNC. For the parent species the molecular constants obtained are B0 = 45332.005(40) MHz and D0 = 0.1019(50) MHz. Structural parameters derived from the ground state rotational constants of this linear molecule are r(H-N) = 0.987 (3) Å and r(N-C) =1.171 (4) Å.