introduce a method based on sequential application of vibrational predissociation spectroscopy to explore the high-amplitude rearrangements available in a small H-bonded complex that is vibrationally excited within a larger Ar cluster. The weakly bound Ar atoms play the role of a solvent in mediating the energy content of the embedded system, ultimately quenching it into local minima through evaporation. We demonstrate the approach on the NO2-center dot H2O binary hydrate, which is known to occur in two nearly isoenergetic isomeric forms. The scheme involves three stages of mass separation to select a particular NO2-center dot H2O-Ar-m parent ion cluster prior to vibrational excitation and then isolate the NO2-center dot H2O-Ar fragment ions for interrogation using resonant vibrational predissociation with a second infrared laser. The initial vibrational excitation selectively energizes one of the isomers through one of its characteristic resonances while the predissociation spectrum of the NO2-center dot H2O-Ar fragment encodes the distribution of isomers present after Ar evaporation. Isomerization from the front- to backside form is found to occur upon excitation of the NO stretch near 1200 cm(-1); although the reverse reaction is not observed upon excitation of the NO stretch, it is observed upon excitation of the higher-energy OH stretching fundamental near 3000 cm(-1). We discuss these observations in the context of the calculated isomerization energetics, which focus on the minimum energy structures for the isomers as well as the transition states for their interconversion.