This project is to develop an instrument capable of measuring the concentration of torpospehric HO2 directly using tunable infrared diode lasers. The proposed instrument would use a novel multipass cell which maximizes the optical path-length while minimizing the cell volume and therefore also the HO2 residence time and wall loss. The Phase I effort will focus on testing a prototype multipass cell and on choosing the best spectral region for monitoring HO2. This evaluation will be based, in part, on HO2 pressure broadening coefficients which will be measured in Phase I.
