Meanwhile, continuum solvation models, also known as implicit solvation or implicit solvent models, depict a solvated molecule/ion at an atomic level of detail inside an electro-static cavity of molecular size and shape, surrounded by the solvent represented as a dielectric medium. In the electrostatic theory of dielectric media, the medium is characterized by a relative permittivity, which is a scalar function of position for isotropic non-homogeneous media. Simple continuum solvation models usually treat the solvent as a continuous uniform and homogeneous medium, avoiding issues related to the thermal equilibration of the solvent. These models also enable the calculation of solvation energies without any background noise from solvent-related disturbances. Typically, the relative permittivity is assumed to be the bulk solvent static dielectric constant outside the solute cavity and is set to a smaller value inside the cavity. This smaller value is often chosen as unity, corresponding to the relative permittivity of vacuum, which is appropriate with the explicit treatment of the solute polarization. For the most common continuum solvation models, such as the conductorlike screening model (COSMO) or the polarizable continuum model (PCM), the solute molecule is surrounded by a continuum polarizable medium. The interface between the solute and the continuum solvent is defined by a cavity formed by overlapping spheres centered on atoms or atomic groups. The polarization of the surrounding medium is represented by point charges positioned at the surface of the molecular cavity. However, applying this approach can give rise to various problems, particularly in the computation of the forces, where discontinuities arise due to the discrete nature of the polarization charges. To avoid this problem, Gaussian charge distribution can be used instead of point charges, leading to a smoother transition between solute and solvent.