The luminescence lifetime of neodymium(III) in aqueous and organic solutions has been measured for the first time, and the effects of solvent deuteration on the excited state decay kinetics investigated. We have shown that the emissive 4F3/2 state is very short lived in water, τ = 29 ± 3 ns, and the lifetime increases significantly upon changing to D2O, τ = 152 ± 7 ns. Complexing to polydentate ligands such as EDTA increases the lifetime due to the reduced solvation of the ion by water. In organic solvents the lifetime of the excited state of the ion is affected by both the presence of C-H and O-H oscillators; the latter are much more efficient at deactivating the excited state.
