Anapole moments of atoms

We analyze the anapole moment or toroidal dipole moment (TDM) of an atom, resulting from the weak interaction between electrons. A simple estimate can be made if the electron density is assumed to be constant. The TDM is found to grow like Z4/3, reaching approximately (eGF/{}c) for the heaviest atoms. An algorithm for calculating the TDM of an atom with a slowly varying electron density is derived using a unitary transformation which removes the weak interaction from the Hamiltonian. We have not attempted to apply this method, but it appears to be a useful method for calculating anapole moments and other effects of weak interactions in complex atoms.