Fig. 3.

The electrostatic energy of chiral and achiral clusters for varying geometric parameters. (A) Two parameters that characterize the cluster configuration. $h$ is the separation between the central dimer and the substrate; $\theta$ is the angle of the petal rotation. For clarity, the central dimer is not shown. (B) The electrostatic energy of a tetramer vs. rotation angle for different $h$. All geometric and electric-field parameters in the calculation correspond to the typical experiment conditions shown in Fig. 1. See text for details. (C) The theoretical phase diagram for chiral clusters (shaded area enclosed by the dashed lines), as predicted by the induced electrostatic model. Red squares and blue triangles indicate chiral and achiral clusters observed in experiments, respectively.