The Visible Absorption Spectrum of ¹⁶OBr¹⁶O and ¹⁸OBr¹⁸O Isolated in Solid Ne

Abstract

The visible absorption spectrum of OBrO isolated in solid Ne is recorded in the 15 800−20 500 cm-1 region. Unlike that reported previously for OBrO in solid Ar, the spectrum in solid Ne has sharp zero-phonon lines (ZPL) exhibiting short progressions of bending (ν2‘) mode built upon a long progression of symmetric stretching (ν1‘) mode. Use of 18O isotopic labeling resolves discrepancies in vibrational assignments proposed previously. Fitting of the wavenumbers of ZPL yields T0 = 15 818.4 ± 0.2, ω1‘ = 642.77 ± 0.13, ω2‘ = 223.21 ± 0.43, x11‘ = −2.85 ± 0.01, x22‘ = −1.07 ± 0.13, and x12‘ = −2.49 ± 0.04 cm-1 for the C2A2 ← X2B1 transition of 16O79Br16O and T0 = 15 832.0 ± 0.2, ω1‘ = 612.49 ± 0.12, ω2‘ = 214.01 ± 0.39, x11‘ = −2.61 ± 0.01, x22‘ = −1.28 ± 0.12, and x12‘ = −2.63 ± 0.04 cm-1 for 18O79Br18O. A weak line at 16744.3 cm-1 may be assigned as to yield 2ν3 = 925.7 cm-1 for 16O79Br16O. Observed spectral parameters agree well with high-level theoretical predictions by Peterson.