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Collisional Excitation of H2O and CO2 by O(3P) Atoms

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Final technical rept. 1 Oct 79-11 Sep 80,

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Theoretical calculations of the molecular excitation cross sections for O3P H2O1A1 and O3P CO2 1 sigma g collisions were made as a function of velocity over the range 2-10kmsec. Potential surfaces for these reactions were computed using the many body perturbation technique. Trajectory calculations were performed with a Monte Carlo quasi-classical trajectory technique. To obtain an accurate analytical fit of the potential surface a many body force field was employed. Also to obtain good action angle variables a technique was developed to perform final state analysis. The results for H2O are insensitive to within a factor of 2 for substantial changes in the fit parameters. This provides a measureable degree of confidence of the predicted results. Representative values for H2O 001 0 are 2.0 x 10 to the minus 7th power sq cm at 4kmsec and 2.0 x 10 to the minus 16th power at 6kmsec. The results for CO2 0 are not as reliable due to the use of a simplier fit of the surface. The results for C02 show that excitation of NNI states is more probable by up to two orders of magnitude than direct excitation of the 001 state. If radiation from the 001 state is observed then a multiple collision environment probably exists. Representative values for CO2 001 0 are 3.0 x 10 to the minus 19th power at 6kmsec and 2.5 x 10 to the minus 18th power at 8kmsec.

Subject Categories:

  • Atmospheric Physics
  • Atomic and Molecular Physics and Spectroscopy

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