High-resolution ion mobility studies of sodium chloride nanocrystals

High-resolution ion mobility measurements have been used to examine the geometries of (NaCl)nCl− clusters with up to 49 NaCl units. Steps in the relative inverse mobilities as a function of the number of NaCl units are due to completion of the 4 × 3 × 3, 4 × 4 × 3, 4 × 4 × 4, and 5 × 4 × 4 cuboids. For clusters with more than 30 NaCl units several families of isomers, with different cuboid or incomplete cuboid geometries, have been resolved at room temperature. The resolved isomers are assigned to specific geometries by comparing the measured mobilities to mobilities calculated for geometries optimized using an ionic potential.