In QM/MM calculations, a key aspect is the effective description of the interactions between the QM and MM regions. Two major embedding schemes are commonly used: mechanical embedding and electrostatic embedding. In general, the electrostatic embedding scheme offers greater accuracy and is more widely used in computations. In this scheme, the QM system is influenced by the electrostatic potential provided by the MM environment, and the MM portion interacts with the charge obtained from the quantum mechanical calculations of the QM system. Additionally, building upon the electrostatic scheme, polarization of the MM system may be considered through polarized embedding using polarizable force fields. In the conventional QM/MM electrostatic embedding scheme, the total energy of the whole system can be decomposed into three parts