UBC Theses and Dissertations
On the ortho - para enhancement of molecular iodine by selective laser excitation Booth, James L.
Based upon the results reported by Balykin, V. S.r Letokhov, V. S., Mishen, V. I., and Semchishen, V. A., Chem. Phys., 17, 111 (1976), an attempt was made to shift the ortho-iodine to para-iodine ratio by (1) selectively predissociating the ortho-iodine molecules with the 5145 A argon ion laser line and (2) by reacting the selectively excited ortho molecules with the scavengers, 2-hexene, acetylene, nitric oxide, nitrosyl chloride, and ethyl iodide. In both cases the ortho to para ratio was monitored via the fluorescence induced by a scanning dye laser beam. Neither tactic prooved effective, in contradiction with the aforementionned authors. In the case of systems containing low pressures ' of iodine' vapour alone, time dependent differential quenching of the vibrational [mathematical formula omitted] transitions was observed attributed to outgasing of the test cells over the course of the experiment and may be the cause of the apparant shift claimed by Letokhov et al. In mixtures of iodine and scavenger, the null result was probably due to the formation of radical chains during the photo-induced reactions capable of rapidly relaxing any shift that had occurred.
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