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A mass-independent sulfur isotope effect in the nonthermal formation of S sub 2 F sub 10

Thesis/Dissertation ·
OSTI ID:6902263
A non mass dependent sulfur isotope effect is present in the rotationally symmetric S{sub 2}F{sub 10} produced in an electrical discharge through sulfur tetrafluoride. A similar mass independent isotope effect was observed in the product S{sub 2}F{sub 10} from the electrodissociation of SF{sub 5}Cl and the photochemical reaction between F{sub 2} and SF{sub 4}. The mass independent mechanism is shown to be operative in the reaction of two molecule of SF{sub 5} to form S{sub 2}F{sub 10}. The effect was not observed in the S{sub 2}F{sub 10} formed in the thermal decomposition of SF{sub 5}Cl or the thermal reaction between F{sub 2} and SF{sub 4}. The mass independent effect is not operative in thermally activated systems regardless of the symmetry of the products as predicted by the difference in lifetimes model. Mass dependent effects such as sulfur isotope exchange and secondary dissociation reactions are found to be significant processes for the system under study. The role of symmetry and a non thermal mode of excitation in non mass dependent isotope effects is strengthened. The search and characterization of mass independent effects is extended to sulfur containing molecules.
Research Organization:
California Univ., San Diego, CA (USA)
OSTI ID:
6902263
Country of Publication:
United States
Language:
English