𝐸 𝑠𝑡𝑎𝑡𝑖𝑐 is calculated by approximating the in vacuo electronic density of the QM part using MBIS partitioning. That is, the total density is described as the sum of atomic densities, consisting of a core charge (𝑞 𝑐𝑜𝑟𝑒 ) and a valence Slater density characterized by the valence charge (𝑞 𝑣𝑎𝑙 ) and the valence shell width (𝑠):