Our first completed photo-musr experiment on 6,13-bis(tri-iso propylsilylethynyl) pentacene (TIPS-Pn) has recently been accepted for publication. We observed a significant light-induced change in amplitude of one of the ALC resonances. The timescale of this light-induced change corresponds to two known transient species. We have interpreted this as a modification of the chemical reactivity of the molecule and Mu as a result of the excitation. However, all of our results to date are qualitative. We have thus far only been able to show that there is an increase in the muonium reaction rate as a result of the excitation, but we have been unable to say how large the increase is. Given that the reaction should be diffusion limited, and that we need to estimate the reactivity of each adduct independently, we plan to perform is a concentration dependent measurement of ALC amplitude.