9320589 Shemansky In the upper atmosphere of the Earth, the energy budget is controlled by both particle collision processes and direct interaction of solar radiation. In response to the need for accurate atomic and molecular properties in order to understand the processes, the University of Southern California (USC) and the Jet Propulsion Laboratory (JPL) of the Calfiornia Institute of Technology have established a program which combines laboratory measurements and non-linear modeling of excitation reactions. The present award will continue in the examination of species critical to the understanding of the observed phenomena. Crossed beam excitation and photoabsorption measurements will be used to define accurate excitation cross sections and other basic atomic and molecular properties such as predissociation fractions required for atmospheric models. Calculations of the combined detailed collisional and radiative non-linear volumetric processes will be produced for utilization by the larger atmospheric models that other researchers have established. In this three-year renewal task plan USC-JPL will concentrate on the species: N2, O2, NO, N, O, H, and their ions the most abundant atomic and molecular species in the upper atmosphere and the species ubiquitously observed by earth orbiting satellites (RAIDS, DMSP, Polar Bear, HUP, SMEX, Aura) equipped with UV sensors. In addition for UV calibration purposes in laboratory and spaceflight instrumentation the target gas H2 will be reexamined to resolve cross section discrepancies. To carry out the measurements JPL will utilize three fully operational UV spectrometers, including the highest resolution single scattering UV instrument in the U.S., a new 3m high resolution spectrometer ( = 67000) with extreme ultraviolet (EUV) and vacuum ultraviolet (FUV) array detectors. ***
