In the QM/MMPol approach, the MM part is described as a set of fixed point charges and isotropic polarizabilities. The polarization of the environment is described as a set of induced dipoles generated at each MM site by the QM electron density and all the other MM fixed charges and induced dipoles. In this way, the mutual polarization between the QM and MM parts is explicitly considered, and the instantaneous response of the MM part to the electronic transition is taken into account.