Atomic sodium is released into the lower thermosphere and upper mesosphere by ablative vaporization of meteors and meteorites. The resulting free atomic sodium layer near 90 km is the source of the chemiluminescent upper stratosphere the resulting NaO, NaO2 and NaOH can react with gaseous HC affecting the chlorine and ozone chemistry of the upper atmosphere. The reactive and photolytic processes controlling the sodium airglow as well as the chemical evolution of mesospheric and stratospheric sodium have use of molecular beam, fast flow reactor, and laser photolysis techniques to sections and product branching ratios necessary to fully model the thermospheric and mesospheric chemistry of gaseous sodium compounds. The study of the chemistry of sodium in the upper atmosphere is important because the sodium layer is an indicator of dynamical motions in the 80-120km region of the atmosphere. When probed by LIDAR the layer shape reveals atmospheric waves and winds and temperature changes, information which it is hard to obtain otherwise. These studies of the chemistry of the sodium layer have long been needed to understand its formation and variations, and Drs. Herschbach (who recently received a Nobel Prize) and Kolb are leading scientists in the field.
