Improved spectral parameters for the three most abundant isotopomers of the oxygen molecule

Line positions, intensities, transition-moment squared, and lower state energies are calculated for the three most abundant isotopomers of the oxygen molecule in the terrestrial atmosphere, O-16(2), (OO)-O-18-O-16, and (OO)-O-17-O-16. All lines passing a wavenumber dependent cutoff procedure (3.7 x 10(-30) cm(-1)/(molecule cm(-2)) at 2000 cm(-1)) are retained for the 1996 HITRAN database. Halfwidths as a function of the transition quantum numbers are determined from the available experimental measurements. Explicit expressions are obtained relating line intensities to the transition-moment squared, the vibrational band intensity, and the electronic-vibrational Einstein-A coefficient. The statistical degeneracy factors are presented and misuse of these factors in previous works is explained. Finally, band-by-band comparisons between the new calculations and the data from the previous HITRAN database are made. (C) 1998 Elsevier Science Ltd. All rights reserved.