The 266 nm laser desorption ionization of frozen CeCl 3 /D 2 O solutions at power densities of about 3 x 10 8 W/cm 2 is studied. Characteristic ionic species desorbed include D 2 O + , D 3 O + . (D 2 O) 0 - 5 , Ce + , CeO + , and CeO + (D 2 O) n . Large quantities of D 2 O vapor are released for an extended period of time. The velocity distributions of these species are analyzed to provide insight into their formation mechanisms. The hydrated metal ion in the frozen bulk sample absorbs the excitation photon and initiates an explosive desorption that ejects, among other species, a CeO + ion that then becomes a nucleation core onto which water molecules are sequentially attached. Energy relaxation into the ice matrix induced water evaporation/sublimation that lasted for 300 μs after the 10 ns laser pulse. The experimental data strongly suggest that CeO + (D 2 O) n are formed through a condensation mechanism instead of arising from dissociation of directly desorbed higher hydrates. The energy-sink role of the ice matrix and its low critical temperature in vacuum resulted in the release over a prolonged period of a very slowly drifting atmosphere of D 2 O vapor that acts to retard the explosively ejected CeO + core ions through D 2 O pickup/condensation and unreactive inelastic collisions.