Structure of 1-naphthol-water clusters in the S1 state studied by UV-IR fluorescence dip spectroscopy and ab initio molecular orbital calculations

► IR spectra of 1-naphthol-water clusters in S1 were observed. ► Theoretical calculations in S1 reproduced the observed spectra. ► Cyclic hydrogen-bond structures around OH in S1 were concluded. ► Local hydration around OH does not promote excited state proton transfer.