Debye. Accurate quantum alchemy predictions are required to search for more desirable molecules. EDS was calculated in the equilibrium geometries of the derivatives. EDSs in ascending EDS order can be found in Figure . We discuss possible improvements for precise molecular design. To improve the accuracy of APDFT, assuming convergence, the perturbation expansion order must be increased. Analytic derivatives of energy and electron density 33, 50-52 allow numerically stable yet computationally efficient evaluations of higher-order APDFT. Finite differences are also useful for systematically increasing the expansion order. A hybrid approach of high-and low-level reference theories for the derivatives of the electron density is effective for reducing the computational cost of higherorder APDFT calculations. A very recently developed alchemical integral transformation (AIT) transforms the integral in APDFT, allowing the calculation of the target system from only the electron density of the reference system. We believe that advances in quantum alchemy will allow more precise molecular design by MDM.