Centrifugal Distortion Effects and Structure of Hydrazoic Acid from the Millimeter Wave Rotational Spectra

The rotational spectra of two 15N-substituted species of hydrazoic acid have been investigated. The values of the rotational constants are: H15N14N14N: A0=619 916 Mc/sec,B0= 11 667.54 Mc/sec,C0= 11 427.86 Mc/sec,H14N14N15N: A0=616 868 Mc/sec,B0= 11 641.76 Mc/sec,C0= 11 405.08 Mc/sec.With the aid of the rotational constants for H14N3 and D14N3 the following structural parameters were obtained: r(N1–H) =0.975±0.015 Å,r(N1–N2) =1.237±0.002 Å,r(N2–N3) =1.133±0.002 Å,∠HN1N2=114∘ 7.8′±30′.An important part of this study was the investigation of the centrifugal stretching behavior exhibited by HN3 and its isotopic species. It has been found that even at low J the introduction of P6 distortion terms for higher K—1 transitions is essential to accurately account for the observed rotational frequencies.