A point dipole with dipole moment p is located at the point x 0 . From the

Question:

A point dipole with dipole moment p is located at the point x₀. From the properties of the derivative of a Dirac delta function, show that for calculation of the potential Ф or the energy of a dipole in an external field, the dipole can be described by an effective charge density

Ρ_eff(x) = -p • Ñ δ(x – x₀)