The dispersed fluorescence spectra have been measured for the 7AI–(H 2 O) n (n=1–3) clusters in a supersonic free jet expansion by exciting various vibronic bands in the S 1 state. There has been controversy about the occurrence of the excited-state proton transfer in the n=2,3 clusters. The absence of visible fluorescence from the tautomer forms of 7AI–(H 2 O) n (n=1–3) indicates that the full tautomerization due to photoinduced excited-state proton transfer does not occur during the lifetime of the S 1 state of the normal form each cluster.