The detailed understanding of the deposition and transfer of energy in the upper atmosphere requires a detailed understanding of the basic interactions between the various ions, atoms, and molecules in the atmosphere. Laboratory measurement of these properties is complicated because of the many states involved. This award provides continuing support for laboratory measurements aimed at determining important cross sections for interactions between selected states involving the aeronomically important ion O+ and the N2 molecule. Similar reactions of generally lesser importance involving other atmosphere species can also be studies. Especially important is the prospect of obtaining results at the low electron energies of most importance for aeronomy of the earth's atmosphere. The PI has made important progress in developing specialized equipment for this research, and it is expected that the results of this work will be important for many fundamental problems in the understanding of the atmospheres of the terrestrial planets.
