The ν2 and ν4 IR bands of SO3

Analysis of ν2, ν4 Infrared Hot Bands of 32S16O3: Resolution of the Puzzle of the ν1 CARS Spectrum

“…The upper states of these transitions are interconnected through the same Coriolis interaction that couples ν 2 to ν 4 and that has been treated in several earlier papers (2)(3)(4). In addition there is a coupling between the l = 0 and l = ±2 components of 2ν 4 , similar to what was found for 2ν 3 (2). We have also identified more than 400 100 0 0 0 -000 0 1 1 transitions to upper state levels that are mixed but are at…”

“…Using the same spectra for which we had identified 4106 transitions due to ν 2 and ν 4 , we have now been able to assign a large number of transitions to the hot bands 020 0 0 0 -010 0 0 0 , 010 0 1 1 -010 0 0 0 , 010 0 1 1 -000 0 1 1 , 000 0 2 0 -000 0 1 1 , and 000 0 2 2 -000 0 1 1 . The upper states of these transitions are interconnected through the same Coriolis interaction that couples ν 2 to ν 4 and that has been treated in several earlier papers (2)(3)(4). In addition there is a coupling between the l = 0 and l = ±2 components of 2ν 4 , similar to what was found for 2ν 3 (2).…”

“…In the first paper of this series (1) we presented the CARS spectra of several isotopomers of SO 3 . The spectra were clearly abnormal and at that time it was speculated that the peculiarities of the spectra could probably be explained by interactions with the nearby levels of 2ν 4 . We have now used an analysis of the hot bands accompanying the ν 2 and ν 4 bands to quantify the interactions with ν 1 and to obtain a calculated CARS spectrum for ν 1 that is in excellent agreement with the observed spectrum.…”

“…In all, 3123 hot-band transitions were fit with an overall RMS deviation of 0.000 12 cm −1 . Fermi-resonant interactions serve to couple the 2ν 4 (l = 0) and 2ν 2 levels to those of ν 1 . Martin (5) has performed an ab initio calculation of the force field for SO 3 and calculates the cubic potential constants k 144 and k 122 that respectively govern these interactions.…”

The HITRAN 2004 molecular spectroscopic database

“…This entry was based on the experimental data of Maki and co-workers [499][500][501][502] with relative transition intensities scaled by the absolute values computed ab initio by Underwood et al [503] . Also included were 25 pure-rotation transitions observed by Meyer et al [504] for which the ab initio intensities of Underwood et al [503] were used.…”