Infrared Spectrum of Ozone in the 4600 and 5300 cm−1Regions: High Order Accidental Resonances through the Analysis of ν1+ 2ν2+ 3ν3− ν2, ν1+ 2ν2+ 3ν3, and 4ν1+ ν3Bands

Abstract

The very weak bands ν1+ 2ν2+ 3ν3and 4ν1+ ν3of16O3have been observed for the first time, using the Fourier transform spectrometer (FTS) of Reims and the usual experimental setup providing a large productp × lof approximately 38 Torr × 36 m. The upper levels of these A-type bands which are rather close in energy (they appear respectively at 5291.722 and 5307.790 cm−1) belong to two different sets of interacting polyads. To correctly reproduce the rotation–vibration energy levels and account for the observed perturbations, both bands are treated in a dyad approximation: the (123) state in the Coriolis resonance with the (330) state, and the (401) state in the Coriolis resonance with the (024) state. The assignments of the rotation–vibration levels of the (123) state are confirmed by measurements of line positions of the hot band ν1+ 2ν2+ 3ν3− ν2which has also been observed for the first time. The fits are very satisfactory: the r.m.s. deviation for 249 energy levels of the (123) state is 2.4 × 10−3cm−1and is 2.0 × 10−3cm−1for 266 levels of the (401) state. These r.m.s. are near experimental accuracy. Transition moments for the three observed bands are determined from measured line intensities.