Determination of the degree of photodissociation of F$_2$ from the temperature measured by the method of intracavity laser spectroscopy

A laser utilizing F$_2^+$ color centers in an LiF crystal was used in intracavity laser spectroscopy to determine the increase in the temperature of molecular fluorine due to the absorption of energy in the course of its flash photolysis. Measurements were based on the temperature dependences of the absorption coefficients of the individual lines of vibrational–rotational transitions in HF molecules which were present in fluorine as a trace impurity. The degree of dissociation of molecular fluorine was determined.