Determination of mobilities of positive ammonium ions in ammonia gas

Drift velocity measurements have been made as a function of the ratio of the electric field intensity to the gas number density, E/N, for the ions NH sub 4 sup +, NH sub 4 sup + (NH sub 3), NH sub 4 sup + (NH sub 3) sub 2, and NH sub 4 sup + (NH sub 3) sub 3 in NH sub 3 gas using a pulsed ion-transit-time method. The reduced zero-field mobilities obtained by extrapolation of these ions to E/N --> 0 ARE 1.49, 1.27, 1.02 and 0.94 cm sup 2 V sup -1 respectively. The values fall below the theoretical calculation predicted by Langevin Mobility Theory. Some studies utilizing an electron-impact ion-source indicates that the mobilities of the ammonium ions in NH sub 3 gas might be influenced by temperature