Tracing chemical changes in the active media of iodine photodissociation lasers

A description is given of a method for determining changes in the concentrations of stable molecules in flash photolysis of active media. In this method flashlamps are switched off rapidly but in a controlled manner by a running arc and the media are then subjected to infrared spectrochemical analysis. The results are given of the application of a method to photochemical changes in CF₃I and (CF₃)₃CI vapors. The time dependences obtained in this way give information on the characteristic sequence of chemical processes which can be used to separate the long-term influence of light on an absorbing gas into three stages: laser, pyrolysis, and quasiequilibrium. The data on the pyrolysis stage can be used to estimate the velocity of pyrolytic bleaching waves, which are propagated in the investigated vapors.