Quadrupolar contact fields: Theory and applications

摘要

Contact terms for the electric dipole and magnetic dipole fields are well known. We give a simple derivation of the contact term of the electric quadrupole field. We then consider applications to the surface potential across a vapor/liquid interface of a nonpolar fluid, an extension of Jackson's theorems for the mean electric fields for spherical regions of space with and without a fixed system of charges, and hyperfine interactions due to the electric quadrupole-monopole and quadrupole-quadrupole interactions of two bound particles of spin one or greater.