Charge transfer reactions between xenon ions and iron atoms in an argon-xenon inductively coupled plasma

Xenon is added to the axial channel of an argon inductively coupled plasma (ICP) at doses up to 1.5% of the aerosol gas flow. Emission is collected from the gas flowing into the sampling orifice of a mass spectrometer (MS). These Xe doses have little effect on the electron density n(e) or on the intensities of Fe (I) emission lines. Certain Fe (II) lines are enhanced when Xe is added, particularly those from Fe+ states that can be populated by near-resonant charge transfer between Xe+ and neutral Fe. Calculations based on measured values of n(e) indicate that Xe+ should be present at densities of up to 7 x 10(14) cm(-3), which should be sufficient Xe+ to drive the proposed charge transfer reactions.