FLASH-PHOTOLYSIS OF IODIDES IN THE PRESEN CE OF QUENCHING GASES .1. PHOTOLYSIS OF C2F5I

A <<quenching buffer>> method was developed for the determination of t he rate constants of the principal reactions involved in flash photoly sis of iodides (RI) in the ultraviolet part of the spectrum in the pre sence of a buffer gas M which acted as a strong quenching agent on the excited state 5(2)P1/2(I) of the iodide atom. The active iodide was in the form of C2F5I molecules, and the buffer consisted of CF3H or H2 O molecules. The rate constants of the following reactions were obtain ed: C2F5+C2F5 --> C4F10, C2F5+I --> C2F5I, I + (RI, M) --> I + (RI,M) , I + I + (RI, M) --> I2 + (RI, M). The collisional broadening coeffic ients lambda were determined for the active transition line of a photo dissociation iodide laser in which the C2F5I, CF3H, and H2O molecules were used. The results demonstrated a correlation between gamma and th e constant representing quenching of I by the buffer M.