In the VL used in this study, the steric effect of a substituent is reproduced using the "ovoid-based" Lennard-Jones potential (hereafter, called as the ovoid LJ potential). The ovoid has seven geometrical parameters a1, a2, b1, b2, c1, c2 and d, which define size, shape, and position of the ovoid (Figure ). Size and shape of the ovoid are defined by stitching one-eighth surface of eight ellipsoids which have either a1 or a2, b1 or b2 and c1 or c2 as their axis (Figure ). The position of the ovoid is defined by the parameter d and the Cl* atom, where the center of the ovoid is located on the direction of the P-Cl* bond, and distance between P and the center of the ovoid is defined by d. By carefully selecting the seven parameters, geometrical features of real substituents can be reproduced using the ovoid (Figure , see Figure and S3 for the detailed procedure and other examples).