We investigated the nucleation process at the molecular level. Controlled sticking of individual atoms onto mass selected clusters over a wide mass range has been carried out for the first time. We measured the absolute unimolecular nucleation cross sections of cationic sodium clusters 
in the range n=25–200 at several collision energies. The widely used hard sphere approximation clearly fails for small sizes : not only should vapor-to-liquid nucleation theories be modified, but also, through the microreversibility principle, cluster decay rate statistical models.
doi:10.1103/PhysRevLett.99.193401
Voir en ligne : Phys. Rev. Lett. 99, 193401 (2007)