where A and B indicate individual molecules in the system, a and b atoms in the respective molecules, Q a t are the static atomic multipole moments of rank t associated to atom a, and T ab tu is the tensor describing the interactions between the multipoles moments Q a t and Q b u . The induced moments ∆Q a t are generated by the electric field created by moments t ′ of atom a ′ ̸ = a in molecule A and the one generated by the moment u of atom b in molecule B: