  Measuring the scintillation light in noble gases is an important detection
technique in particle physics. Numerous rare event searches like neutrino beam
experiments, neutrino-less double beta-decay, and dark matter searches use
argon-based detectors. In liquid argon, the light yield can be enhanced by the
addition of a small quantity of xenon, where $\sim 10 - 1000$ ppm are added.
The general enhancement mechanism and its pathway via an energy transfer
between argon and xenon excimers is well known, however the importance of
absorption of argon excimer emission by atomic xenon has not been fully
appreciated. This absorption significantly reduces the light yield in
commercially available argon which contains trace amounts ($\rm \sim 0.1$ ppm)
of xenon. The addition of a small xenon dopant of $\sim 10$ ppm recovers this
lost light resulting in an increased light yield over un-doped argon of about a
factor of two. In this paper we introduce a model for the light production in
xenon doped argon, including absorption and re-emission, and compare it to the
measured time dependence of light emission in xenon-doped argon.
