The scaling law of cluster sizes revisited: Clusters formed via coexpansion of a molecular and a rare gas species.

[Display omitted] • This work presents a facile method of cluster size characterization of neat atomic Ar clusters, neat molecular 1, 3, 5‑trichlorobenzene clusters, and core (1, 3, 5-trichlorobenzene) – shell (Ar) clusters. • The experimental results are in qualitative agreement with the semi-empirical scaling law, but effects of the stagnation temperature and pressure on the cluster size are quantitatively different from those predicted by the scaling law. • Our method measures the size of the core and the total size of the cluster, therefore offers information on the thickness of the shell of the core–shell cluster. We report experimental measurements of cluster sizes formed from supersonic expansion of two different species based on the time-of-flight principle. Argon clusters containing aromatic molecules are ionized at 266 nm at a low laser intensity. A high voltage is used to accelerate the heavy cluster ions thereby increasing the sensitivity of a microchannel plate detector. Our measurements of argon clusters, neat molecular clusters, and molecular-Ar clusters, are all in qualitative agreement with results predicted from the scaling law, but the fitting exponents for the dependence of cluster sizes on both the stagnation pressure and temperature are different. [ABSTRACT FROM AUTHOR]