The reaction between atomic hydrogen and ozone in the upper mesosphere produces vibrationally excited hydroxyl, resulting in two important consequences. First, excited hydroxyl radiative decay produces the hydroxyl nighttime airglow layer, used extensively in proving the hydroxyl chemical production rate and in studying wave phenomena. Second, the collisional relaxation of highly excited hydroxyl is key to nocturnal heating in the upper mesosphere. Mesospheric energy budget models rely on accurate understanding of hydroxyl product distribution and its collisional and radiative decay. Despite the importance of this process, a significant fraction of the reaction exothermicity is not accounted for in existing measurements. Thus, the investigator is conducting an in-depth study of the atomic hydrogen and ozone reaction, where all possible hydroxyl nascent product state populations are detected and quantified. His measurements are reducing the uncertainly in necessary input parameters to mesospheric energy budget models.
