Jonathan Fischer

Total internal partition sums for molecular species in the 2000 edition of the HITRAN database

Abstract Total internal partition sums (TIPS) are calculated for all molecular species in the 2000 HITRAN database. In addition, the TIPS for 13 other isotopomers/isotopologues of ozone and carbon dioxide are presented. The calculations address the corrections suggested by Goldman et al. (JQSRT 66 (2000) 455). The calculations consider the temperature range 70– 3000 K to be applicable to a variety of remote sensing needs. The method of calculation for each molecular species is stated and comparisons with data from the literature are discussed. A new method of recall for the partition sums, Lagrange 4-point interpolation, is developed. This method, unlike previous versions of the TIPS code, allows all molecular species to be considered.

Half-widths of H216O, H218O, H217O, HD16O, and D216O: I. Comparison between isotopomers

Abstract Pressure-broadened half-widths are determined using the complex Robert–Bonamy (CRB) formalism for five isotopomers of water vapor. The calculations are made with nitrogen and oxygen as the perturbing gases. The intermolecular potential is taken as a sum of electrostatic contributions, Lennard-Jones (6–12) atom–atom, and isotropic induction and dispersion components. Calculations made using recently determined Lennard-Jones (L-J) parameters for deuterium are compared with previous calculations that utilized only the hydrogen L-J parameters. The dynamics of the collision process are correct to second order in time. Ratios of the half-width of the principal isotopomer to the other isotopomers are determined and discussed with particular emphasis on predicting half-widths of the lesser isotopic species from the values for the principal species.

Temperature dependent pressure induced lineshape of O3 rotational transitions in air

The pressure induced broadening of a series of pure rotational transitions of ozone have been measured as a function of temperature. Results of experiments are compared with calculations employing the complex semiclassical theory of Robert and Bonamy. This set of rotational transitions is the dominant feature of the millimeter and submillimeter ozone spectra to be measured in the upcoming EOS-MLS mission.

Half-widths of , and D216O: II. Comparison with measurement

Abstract Pressure-broadened half-widths of ν2 transitions are determined using the complex Robert–Bonamy formalism for four isotopomers of water vapor: H 2 18 O , H 2 17 O , HD 16 O , and D216O. The calculations are made with nitrogen and oxygen as the perturbing gases. A survey of the literature revealed N2-broadened measurements of 365, 61, 990, and 545 ν2 transitions of the H 2 18 O , H 2 17 O , HD 16 O , and D216O isotopomers, respectively, and O2-broadened measurements of 266 and 134 ν2 transitions of the HD16O, and D216O isotopomers, respectively. The calculated and measured half-widths are compared. In general, good agreement is observed when the most recent atom–atom constants are employed.

Total internal partition sums for molecules of astrophysical interest

Abstract Total internal partition sums (TIPS) are calculated for several molecules, which are abundant in non-terrestrial planetary atmospheres. For all molecules, calculations are performed for the most abundant isotopic species. Partition sums for lesser abundant isotopomers of several molecules are determined as well. The calculations are made for temperatures between 70 and 300 K . The resulting TIPS are fit to a polynomial expression, which is fourth order in temperature. The methods of calculation of the TIPS, the convergence, and the quality of the polynomial fits for each isotopomer are discussed.