Figure 1: Illustration of the preoptimization procedure using the old surface of ozone. The MEP is shown as blue curve. The covalent well and the vdW well are seen. Horizontal axis gives the internal hyperradial coordinate of O3. The cut-off energy is shown by dashed line. The 500 data points are shown as red dots: (a) the initial placement of points according to the worst case scenario, (b) the final optimized set of points obtained after 5,000 iterations.