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Single molecules in soft matter: dynamical heterogeneity in supercooled liquids and glasses

Final Report Summary - SIMOSOMA (Single molecules in soft matter: dynamical heterogeneity in supercooled liquids and glasses)

The project has spawned new optical methods for the detection and study of single molecules and single nanoparticles. The three main achievements have been:
1. The optical detection of the absorption of a single molecule at room temperature (instead of its fluorescence as in conventional methods). This weak absorption signal corresponds to the ratio of areas of a 1-Euro coin to that of a football field.
2. The detection of a single protein molecule when it binds to the tip of a gold rod 40 nm long. The signal involves only the refractive index of the molecule, not its absorption or emission of light.
3. The discovery of fluorescence enhancement by more than 1000 in the vicinity of the tip of a nanorod, generalizing single-molecule detection to many emitting molecules with low quantum yields.
In addition to these methodological developments, the project also led to the discovery of new fundamental truths about nature. Two examples are the damping of acoustic vibrations by a thin water layer between a nanoparticle and its substrate, and the unexpected presence of 'whey and curd' structures 30 K above the glass transition of supercooled glycerol.