Relaxation Processes of Vibrationally Excited H2O in the Mesosphere and Thermosphere
Abstract
A review of rate constants for the relaxation of vibrationally excited H2O is presented. This evaluation is the second in a series of reports intended to improve the state-of-knowledge regarding the chemical kinetics of the mesosphere and thermosphere. The vibrational levels discussed are limited to those presumably populated at altitudes > 50 km. The collision partners of interest are the major constituents in the upper atmosphere. The recommended rate constants have been implemented in the Strategic High Altitude Atmospheric Radiance Code (SHARC 2.0), which is used to calculate background infrared radiance. Recent laser induced fluorescence experiments have improved the temperature dependent data for the self relaxation of H2O and for the relaxation by O atoms. However, the temperature dependences of the relaxation pathways enabled by the dominant atmospheric species, N2 and O2 have not been well characterized. Ambient temperatures in the mesosphere and thermosphere typically range from 190 to 1300 K. We have compiled the available data for each relevant relaxation partner in order to obtain temperature functions. Where possible, a linear Landau Teller form was used.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1991
- Accession Number
- ADA241853
Entities
People
- V. I. Lang
Organizations
- The Aerospace Corporation