THE COLLISIONAL QUENCHING OF ELECTRONICALLY EXCITED IODINE ATOMS BY MOLECULAR OXYGEN

Molecular energy transfer processes have recently been the subject of intense study, both theoretically and experimentally. This thesis describes work undertaken to elucidate the deactivation processes in the gas phase interaction of electronically excited iodine atoms (I* (TBOND) 5 ('2)P(, 1/2)) with molecular oxygen.; Electronically excited iodine was created by the pulsed laser photolysis of a variety of aryl, alkyl, an perfluoroalkyl iodides. The kinetics of the deactivation processes were observed using the technique of time-resolved infrared fluorescence which monitored the 1.315 micron emission from the I* (('2)P(, 1/2)).; From the time dependence of the fluorescence, the kinetics of the I*-O(,2) system was derived. The primary mechanism of the I*(('2)P(, 1/2)) deactivation is shown to be an electronic-to-electronic energy-transfer equilibrium process between the iodine and the oxygen, creating electronically excited O(,2)* (('1)(DELTA)(,g)). This is in contrast to an earlier report using similar methods. Also observed were results indicative of a process which rapidly quenches the singlet oxygen. This process is dependent upon the precursor used to generate the initial I*(('2)P(, 1/2)). Although attempts were made to identify the quenching species, its identity remains unclear.; Computer modeling of the proposed kinetic scheme was undertaken to study further the mechanism of deactivation. These results verify the validity of the experimental results.