HR: 0800h
AN: SA11A-1111    [Abstracts]
TI: CROSS-SECTIONS FOR EXCITED STATE NONADIABATIC THERMOSPHERIC REACTIONS
AU: * Coker, D
EM: coker@bu.edu
AF: BOSTON UNIVERSITY, 590 COMMONWEALTH AVE., BOSTON, MA 02215 United States
AU: Dothe, H
EM: dothe@spectral.com
AF: SPECTRAL SCIENCES, INC., 4 FOURTH AVE., BURLINGTON, MA 01803 United States
AU: Chen, L
EM: linachen@bu.edu
AF: BOSTON UNIVERSITY, 590 COMMONWEALTH AVE., BOSTON, MA 02215 United States
AU: Tambouret, Y
EM: yannpaul@bu.edu
AF: BOSTON UNIVERSITY, 590 COMMONWEALTH AVE., BOSTON, MA 02215 United States
AU: Duff, J W
EM: duff@spectral.com
AF: SPECTRAL SCIENCES, INC., 4 FOURTH AVE., BURLINGTON, MA 01803 United States
AB: New methods for treating nonadiabatic excited state reactions are tested using accurate ab initio potentials and nonadiabatic couplings in studies of excited state atom quenching reactions including N($^{2}$D) + O($^{3}$P) \rightarrow N($^{4}$S) + O($^{3}$P) and O($^{1}$D) + O($^{3}$P) \rightarrow O($^{3}$P) + O($^{3}$P). These collision induced electronic transitions (CIET) processes play a crucial role in quenching excited atoms produced by photodissociation, photoionization, and dissociative recombination processes in the thermosphere. Potential energy surfaces and non-adiabatic couplings for these processes computed using the ab initio MOLPRO package will be presented. Energy dependent cross-sections for these CIET processes, obtained from a nonadiabatic mixed quantum-classical surface hopping approach, a nonadiabatic extension to quasiclassical trajectory (QCT) methods, will be compared with the results of exact full quantum close coupled (CC) calculations, to develop an understanding of the conditions under which these nonadiabatic trajectory-based dynamics methods can be reliable. Cross sections calculated for O($^{1}$D) quenching will be compared to currently available values and preliminary computed cross sections for the N($^{2}$D) quenching will be presented.
DE: 0310 Airglow and aurora
DE: 0317 Chemical kinetic and photochemical properties
DE: 0335 Ion chemistry of the atmosphere (2419, 2427)
DE: 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707)
DE: 0358 Thermosphere--energy deposition
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting