Excited state population dynamics of a xenon ac discharge

We measure the time evolution of the – (834.68 nm, air) excited neutral xenon transition lineshape in a xenon 60 Hz oscillatory discharge by applying time-synchronized laser induced fluorescence (LIF) spectroscopy. Two different time-synchronized LIF techniques are demonstrated, yielding consistent results and revealing distinct features: a reduction of peak fluorescence intensity (representative of the state density) is observed at high values of the discharge current, the maximum fluorescence intensity occurs at low values of the discharge current, and the excited state populations quench as the alternating current passes through zero. This behavior is reproduced and explained by collisional-radiative modeling, which highlights the role of collisional and radiative mixing between excited energy states throughout the current cycle.