Chemical laser probing of reactions

The use of a chemical laser as a probe make easy the direct absorption or amplification of light by a reactive medium, at a given precise time. If we make such a measurement with each vibration-rotation transition yielded by the laser probe one gets a direct view on the evolution of population of the synthetized molecules during a chemical reaction. As a result we have a direct knowledge of the relative formation rates of the molecules on various vibrational levels and of the temperature evolution in the reactive gas. When the reaction has stopped, the decay of the population on each vibrational level gives a measurement of the corresponding vibrational relaxation time. Results will be presented concerning the reaction of atomic hydrogen with chloride, nitrosyl chloride.