In recent experiments on sodium chloride clusters, structural transitions between nanocrystals with different cuboidal shapes were detected. Here we determine reaction pathways between the low-energy isomers of one of these clusters, ${\mathrm{}\left(\mathrm{NaCl}\right)\mathrm{}}_{35}{\mathrm{Cl}}^{\mathrm{-}}.$ The key process in these structural transitions is a highly cooperative rearrangement in which two parts of the nanocrystal slip past one another on a {110} plane in a $〈11¯0〉$ direction. In this way the nanocrystals can plastically deform, in contrast to the brittle behavior of bulk sodium chloride crystals at the same temperatures; the nanocrystals have mechanical properties which are a unique feature of their finite size. We also report and compare the global potential-energy minima for $(\mathrm{NaCl}{)}_N{\mathrm{Cl}}^{\mathrm{-}}$ using two empirical potentials, and comment on the effect of polarization.

• Received 28 July 1998

DOI:https://doi.org/10.1103/PhysRevB.59.2292