Intensity and Interactions of Atmospheric Ions with Organic Contaminants

Abstract

Interactions of ions with trace impurities in the atmosphere can lead to dramatic changes in the ion species even though the reactants are present in only trace amounts. The processes of charge exchange, ion clustering and proton transfer are found to convert ions of primary air species into those characteristic of trace constituents in the mixture. For these measurements we have used a drift cell-mass spectrometer combination to mass analyze ions produced from arc and glow discharge sources in air and air-like mixtures at pressures up to 5 torr*). The interactions of the ions with trace impurities present in the drift cell dominate the ion chemistry, with the result that ions extracted from the gas after reaction are completely different from those produced by the primary ionization process. The rapidity of these reactions indicates that ions formed in the atmosphere will have their chemistry and identity dominated by trace species present in the atmosphere. These results have been applied to the problem of relay contact activation in which deposition of organic material on low current relay contacts results in an increase in relay arc duration and a consequent increase in relay contact erosion. We will show specific application to the case of ions interacting with organic materials present in the environment surrounding telephone relays.

1 torr = 133 Pa. 1 pascal = N m^-2.