High Resolution FTIR Spectroscopy of Borazine: The Parallel Bands ν8 and ν9 of 10B314N31H6

The high resolution (0.002 cm^–1) FTIR spectra of the A ‐fundamental bands ν₈ and ν₉ of ¹⁰B₃¹⁴N₃¹H₆ were investigated for the first time. Both fundamental bands show a typical parallel band structure, thus confirming the D_3h symmetry of the molecule under consideration. Whilst ν₉ is unperturbed at the present level of precision, ν₈ is heavily perturbed, probably by an α^BB‐resonance with the IR‐forbidden combination tone ν₁₀ + ν₁₇. The molecular constants of the ground state and of the states v₈ = 1 and v₉ = 1, respectively, are given.     

α BB Resonance in the ν8 Band of Borazine –10B

The high-resolution FTIR spectrum of the fundamental ₈ of borazine ¹⁰B₃ ¹⁴N₃ ¹H₆ was reanalyzed taking into account the ^BB resonance with the combination band (₁₀ + ₁₇). A parameter set for the states ₈ = 1 and ₁₀ = ₁₇ = 1, respectively, is given, reproducing the observed spectrum at least up to J = 30 with experimental accuracy.