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A semianalytic model for photo-induced isotopic\ud fractionation in simple molecules

By Mao-Chang Liang, Geoffrey A. Blake and Yuk L. Yung

Abstract

We have developed a semianalytic model for computing the photo-induced isotopic fractionation in simple molecules of interest to the atmospheric science community. The method is based on the Born-Oppenheimer approximation and the Reflection Principle. It has the main advantage of using commonly available input data, namely, the photolysis cross sections for the standard isotopologue/isotopomer and the ground state isotope-specific spectroscopic constants. The isotopic fractionation arises principally from the spectral shift induced by the small difference in zero point energy between isotopologues/isotopomers and the contraction of the wave function due to heavier isotope substitution. The latter effect dominates photolytic fractionation away from the cross section maxima. Our new approach is demonstrated with applications to the diatomic molecules HCl and HI, and the triatomic molecules N_2O and O_3. Agreement between the model and measurements is excellent. New modeling results for the fractionation of ^(15)N^(15)N^(16)O in the stratosphere using the Caltech/JPL two-dimensional model are presented

Publisher: American Geophysical Union
Year: 2004
OAI identifier: oai:authors.library.caltech.edu:34198
Provided by: Caltech Authors

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Citations

  1. (2003). A BornOppenheimer photolysis model of N2O fractionation,
  2. (2001). Absorption cross sections of HCl and DCl at 135–232 nanometers, doi
  3. (1983). Dynamical equations for the Wigner functions, in Energy Storage and Redistributions doi
  4. (1995). higher southern latitudes lower stratosphere, doi
  5. (1999). Orr-Ewing doi
  6. (2000). Spin-orbit branching in the photodissociation of HF and DF. I. A time-dependent wave packet study for excitation from v = 0, doi
  7. (1997). The 18O/16O and 17O/16O ratios in atmospheric nitrous oxide: A mass-independent anomaly, doi
  8. (1993). The D/H ratio and the evolution of water in the terrestrial planets, doi
  9. (1999). Thiemens doi
  10. (1967). Traces of HCl and HF in the atmosphere of Venus, doi

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