Experimental Determination of Nucleation Scaling Law for Small Charged Particles

TL;DR

This study experimentally measures nucleation cross sections of small charged sodium clusters, revealing that traditional hard sphere models fail at small sizes and indicating the need for modified nucleation theories.

Contribution

First experimental determination of nucleation cross sections for cationic sodium clusters across a wide size range, challenging existing hard sphere approximations.

Findings

Hard sphere approximation fails for small clusters

Nucleation cross sections measured for Na+ clusters n=25-200

Implications for modifying vapor-to-liquid nucleation theories

Abstract

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 Na_{n}^{+} 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.