Relaxation processes of vibrationally excited species in the mesosphere and thermosphere

摘要

Abstract: A critical review of rate constants for collisional relaxation processes and spontaneous emission processes in the non-LTE environment between 50 and 300 km is in progress. The infrared radiators considered are CO, H$-2$/O, O$-3$/, NO, CO$-2$/, OH and CH$-4$/. The last major compilation of vibrational relaxation rates relevant to the atmosphere was published by Taylor in 1974. The advent of laser-induced fluorescence techniques during the past two decades has greatly improved the state of knowledge regarding level specific collisional deactivation processes. Additionally, improved measurements of the rovibrational band strengths for H$-2$/O, O$-3$/ and CH$-4$/ have resulted in improved Einstein A coefficients for these species. The rate constants under review are important parameters in models used to predict the dissipation of radiation entering the Earth's atmosphere as sunshine or energetic electrons. They are fundamental quantities in background radiance calculations. The effect of revising the rate coefficients has been illustrated using the Strategic High-Altitude Atmospheric Radiance Code (SHARC 2.0).!29