dipoolmodellering

Dipoolmodellering refers to representing a system’s electromagnetic response by one or more dipoles, typically electric dipoles, which are pairs of opposite charges separated by a distance. The approach is used to simplify complex charge distributions and to describe long-range interactions, polarizability, and radiation, across physics, chemistry, and engineering. The term is common in Danish/Norwegian contexts as well and is closely related to the broader concept of the dipole approximation.

In physics and electrical engineering, the point dipole model approximates a localized source or scatterer by a vector p, the electric dipole moment. The moment is p = ∑ q_i r_i, or for a simple pair, p ≈ q d. The electric potential at position r is V(r) = (1/4πε0) p·r / r^3, and the far-field radiation of an oscillating dipole has characteristic angular dependences. The magnetic dipole moment has analogous definitions. The dipole-dipole interaction energy scales as 1/r^3.

In chemistry and materials science, molecular dipole moments quantify polarity and influence intermolecular forces and spectroscopy. In simulations, fixed or induced dipoles approximate the charge distribution: point-dipole models, polarizable models, and Drude oscillators. Polarization effects and many-body interactions may require beyond-dipole descriptions.

Limitations include the breakdown of the point-dipole approximation at short distances, anisotropic distributions, and complex environments. Dipole modellering remains a foundational tool in modeling long-range electrostatics, dielectrics, antenna design, and molecular interactions.