I. Experimental Determination of Selected Accommodation Coefficients. II. Experimental Determination of the Heat of Iodine

Citation

Angelo, Raymond Louis (1951) I. Experimental Determination of Selected Accommodation Coefficients. II. Experimental Determination of the Heat of Iodine. Engineer's thesis, California Institute of Technology. doi:10.7907/1DD6-8B60. https://resolver.caltech.edu/CaltechETD:etd-03172009-085837

Abstract

In PART I the results of a study of the accommodation coefficient and its dependence on the temperature of the metal surface are described. The following systems were investigated: oxygen on platinum, carbon dioxide on platinum, nitrogen on platinum, carbon dioxide on tungsten, and carbon dioxide on nickel. All systems exhibit similar characteristics; i.e., a rapid rise to a maximum value of the accommodation coefficient in the region of low filament temperatures followed by a gradual decrease to a constant value as the filament temperature is increased, bulb temperature remaining constant. Maximum Constant value Oxygen-platinum .98 .68 Nitrogen-platinum .97 .50 CO2 -platinum .56 .35 CO2 -tungsten .93 .80 CO2 - nickel .68 .47 This general behavior of the accommodation coefficient substantiates findings reported earlier by Oliver (13) for other gas-metal systems. The experimentally determined values of the accommodation coefficient are applied to a theoretical relation obtained by application of the theory of absolute reaction rates (10). The theoretical expression is shown to be in semiquantitative agreement with the experimental data. In PART II the "hot wire" method is used to determine the heat of dissociation of iodine. The experimentally determined value is 36.9 kcal/mole at 600°K. The presently accepted value for this temperature is 35.17 kcal/mole. Provided a wire can be found which is not corroded by fluorine, the present results suggest a useful method for determining the heat of dissociation of fluorine.

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