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Drift velocities and reactions of nitrogen ions have been investigated at 300°K at values of E/N (the ratios of electric field to number density) between 1.5 and 20X10"" 16 V cm 2 , and at pressures between 0.5 and 1 Torr. Ions were produced in a glow discharge and were gated into a drift cell, withdrawn through a slit, and their mass and intensity were determined as a function of the drift time by a mass analyzer. Comparison of experimental results with theoretical calculations allowed the determination of true drift velocities and reaction rates for ions undergoing reaction during the drift time. The ions in nitrogen were found to occur in two groups, N 2 + -N4 + and N + -N3 + , such that interactions within the groups are much faster than any interactions between the groups. Rate constants for the reaction N 2 + +N 2 +N 2 -> N4 + +N 2 were found to vary from 7X10~2 9 to 2X10" 29 cm 6 /sec between E/N of 5X10" 16 and 18X10" 16 V cm 2 , while for the reverse reaction the rates varied from 0.3X10 -13 to 110X10 -13 cm 3 /sec. The pressure dependences of the reaction rates were consistent with a three-body forward reaction and a two-body reverse reaction over our limited pressure range. For the N + -N3 + system, the interaction of N + with the neutral gas to produce N 3 + was observed at E/N =5X10~1 6 V cm 2 with a rate constant of 3X10~2 9 cm 6 /sec. No reactions could be positively identified which produced N + over the range of our experimental parameters.

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The development of an ion-drift cell using mass analysis has enabled the measurement of mobility and identification of six ions in argon. Reduced mobilities of 1.40, 1.95, and 2.40 have been obtained for Ar + , Ar 2 + , and Ar + + in the pure gas, allowing positive identification of ions observed in early experiments by Hornbeck, Biondi, and Beaty. Also, mobilities are obtained for H 3 + , ArH + , and Kr + formed in mixtures of argon with hydrogen and krypton. To determine mobilities in argon, three separate experiments using (1) a conventional parallel-plate ion-drift tube, (2) a modified pulsed Townsend discharge with mass analysis, and (3) a gated Tyndall technique with mass analysis were performed to permit comparison with previous experiments.

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This paper describes a new technique for the determination of diffusion constants of gases in gas-solid systems. The method demands a careful analysis of the transient quantity of gas flowing after the gas pressure at the boundary is discontinuously changed. The exact quantity of gas flowing is recorded by a mass spectrometer. The method was used to study the effect of high tensile stress upon the diffusion constant of helium and other gases in glass. The diffusion constant of helium was found to be a true constant with dilation of the glass until the stress became about one-half the breaking stress of the glass. Beyond this point the diffusion constant increased, and under very high stress was a factor of ten larger than its original value. No apparent change was produced in the glass, and reduced stress gave the same diffusion constant as previously, indicating reversibility of the effect with stress. It was further determined that equal and even larger compressional stresses on the same glass specimen had little or no effect upon the diffusion constant. The effect of shear stress upon the diffusion constant is dealt with in the following paper. The magnitude of the observed increase in diffusion constant is larger by a considerable factor than can be explained by a straight-forward extension of prevalent theories of diffusion in glass. If it is assumed that the glass sample dilates on an atomic scale, i.e., each atom being isotropically displaced by the stress, then calculations show that the diffusion constant should not be strongly increased under stress. Observation of the large increase then points toward the opening of flaws or voids within the glass. Diffusion of hydrogen, heavy water, oxygen, and nitrogen is discussed and upper limits for diffusion of the latter three under high stress are set.

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