In the GEISA-97 cross-sections file, the spectroscopic parameters related to heavy molecules, like the CFC's, are not stored following the usual standard (i.e. via line position, intensity, halfwidth, etc.), but principally as absorption cross-sections determined through the following expression:

where w is a frequency (cm^-1); s(w) is the absorption cross section (cm² molecule^-1); I0(w) and I(w) are the intensities, at the frequency w, of the incident and transmitted radiation, respectively; n is the concentration of the molecules (molecule cm^-3) and l the optical path length (cm). It is the s(w) value derived from high-resolution experimental data that is cataloged in the GEISA cross-sections file.

Since GEISA-92, the GEISA-97 cross-sections databank has been significantly updated and extended. The data on CFC13, CFC14, CFC32, CFC113, CFC114, and CFC115 (Massie et al., 1991; Mc Daniel et al., 1991) have been kept from GEISA92, and the CFC12 existing data (Massie et al., 1991, Mc Daniel et al., 1991) removed. New cross-sections have been cataloged for the following compounds: CFC11 (Li and Varanasi, 1994); CFC12 (Varanasi and Nemtchinov, 1994); HCFC22 (Varanasi et al., 1994 and Clerbaux et al., 1993); HCFC123, HCFC124, HCFC125, HCFC134a, HCFC141b, HCFC142b, HFC152a, HCFC225ca, and HCFC225cb (Clerbaux et al., 1993); HFC32 and HFC143a (Smith et al., 1996, 1998); HFC134 (Smith et al., 1998); N₂O₅ (Massie et al., 1985); SF₆ (Varanasi et al., 1994); ClONO₂ (Orphal et al., 1994). This represents a total of 23 molecules, in the spectral range 556.380-1763.642 cm^-1.
  Table 1, partitioned by molecule, lists the whole contents of the GEISA97 cross-sections file. For each of the 23 molecules, its name and corresponding code for the management of the cross-sections database (see text below) is given in column 1. The atmospheric conditions, temperature (T) in K and pressure (P) in Pa, are listed in columns two and three, respectively. For a given couple, T and P: the fourth column gives the number of available cross-sections (Lines), columns five and six, the minimum (nu.min) and maximum (nu.max) frequency (cm^-1) values, and columns seven and eight, the corresponding minimum (Min.I) and maximum (Max.I) cross-sections values (cm² molecule^-1), respectively. Note that, if the pressure is set to zero, it means, in the case of HFC32, 134a, 134, 143a, 152a, HCFC123, 124, 141b, 225ca, 225cb, that the cross-sections have been measured for a pure vapor (non-air broadened); for other molecules, it means that the the pressure value has not been given explicitly by the authors, but it should correspond to that of the US standard atmosphere, for a given temperature value. The total number of available cross-sections of the related molecule is provided at the bottom of each corresponding sub-table.

New results on CFC's cross sections have been obtained beyond this issue of the database and will be included in the next issue of GEISA. These new data provide an extension of the number of temperature and pressure conditions (more than 50, including polar) for CFC11 and CFC12, and also new results for CF₄ and CCl₄ at more than 50 temperature and pressure conditions (including polar).

  Extractions from this databank can be made thanks to its management software.