where: ∆E is the maximum value at the center of the objective interval (lb, hb). For every objective interval, we construct a LCHFs by adding two HFs with ∆E values of opposite sign, where the one with the lower absolute value has its boundaries equidistant from the outer boundaries of the other by a small magnitude (∼ 0.05Å). While the HFs have the absolute values of their maximum at the center of the inner and outer intervals, the maximum of their sum will be the difference between their respective ∆E values. The same approximation was applied to obtain the tested LCGFs (see the GFs' definition in the SI). As an example, for the objective interval (1.20Å, 2.60Å) and ∆E of 2.0 kcal/mol, the curves plotted in Figure are defined as: