Towards the intensity consistency of the ozone bands in the infrared range: Ab initio corrections to the S&MPO database

High Resolution Infrared Spectroscopy in Support of Ozone Atmospheric Monitoring and Validation of the Potential Energy Function

“…Despite the fact that this value is significantly smaller than the natural width (see below), it limits the influence of the apparatus function (instrumental line shape (ILS)). New spectra were recorded with these Bruker instruments in Deutsch Forschungsanstalt Luft & Raumfahrt (DLR), Oberpfaffenhofen Germany, by Birk et al [ 173 ] and Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphère (LERMA), Paris France, by Janssen et al [ 19 ] in the range of 10 microns, which lead to a precision of a sub percent for intensities, in agreement with ab initio calculations [ 17 , 18 , 24 ] (see Section 5.1 . Recent Results).…”

“…The DMS of [ 133 ] is currently considered to be the most accurate. It was used for ab initio scaling of the ro-vibrational intensities of thirty ozone bands, subsequently validated by atmospheric and laboratory measurements [ 158 ] and included in the last release of the S&MPO and HITRAN databases as described in [ 18 , 24 ]. This DMS was also used for a combined ab initio/empirical line list computed by University College London with collaborators [ 159 ].…”

“…For these reasons, ab initio line intensities were found useful for predicting the intensities of strong unperturbed lines or for producing general scaling corrections with respect to empirical extrapolations throughout the entire vibrational band. This is explained in detail in [ 18 ]. It should also be said that the accuracies are the best in low wavenumber regions (fundamentals and ν 1 + ν 3 ), where they reach the sub percent level.…”

“…In the case of ozone, when relatively large samples are used (using White cell as an example), ozone decomposition occurs, and its quantification can lead to errors of several percent. In these conditions, scaling factors from ab initio intensities improve the consistency among different spectral intervals [ 18 , 158 ].…”

“…The calculated lists include transition frequencies (ν ij ) and intensities ( S ij ), lower energy values ( E low ), and the quantum identification of upper and lower levels. Further, these lists, completed by the broadening (γ air , γ self ) and shifting (δ air ) parameters of spectral lines, are included in spectroscopic databases, such as the S&MPO [ 18 , 21 , 64 ], GEISA [ 223 ], and HITRAN [ 24 , 224 , 225 ] databases. Note that the calculated lists include a much larger number of bands than is shown in Table 6 .…”