MD1 - The transfer chemical laser: A review of recent research

Processes of collisional redistribution of vibrational energy prevail over specific chemical reaction mechanisms in the determination of vibrational energy distributions in present hydrogen halide CW chemical lasers. Despite the resultant relatively modest departures from the Maxwell-Boltzmann form for the distribution of energy among the vibrational levels of product molecules, selective vibrational energy transfer to a second molecule (e.g., CO2) can be an effective method for the production of complete population inversion by the energy release of chemical reactions. This concept has been the basis for the development of the transfer chemical laser (TCL) during the past three years. A summary of recent progress in the development of CW and pulsed DF-CO2transfer chemical lasers is presented. An experiment designed to produce multikilowatt supersonic DF-CO2chemical laser operation with full atmospheric recovery in the exhaust gases is discussed. Recent measurements of key vibrational energy transfer processes are reviewed; such measurements have greatly clarified the kinetic aspects of the HF, DF, HF-CO2, DF-CO2, HCl-CO2and HBr-CO2chemical lasers. The very large values for these key rates (corresponding to about 20 to 200 collisions) can be attributed to energy transfer to rotation under the influence of a sizable attractive intermolecular potential well and enhanced repulsion at close range.