Electric polarizability of atoms and molecules

Abstract Kirkwood's variation method for the calculation of the polarization of an atom or molecule in an external potential V(r), uses a wave function where ψ0 is the wave function in the absence of the perturbation, and the summation is over the electrons. The energy is varied with respect to the parameter μ. In this paper an extension of the method is presented using a wave function This equation is solved numerically for argon, using the Hartree-Fock wave function. The form of u turns out to be nearly quadratic, and shows that almost the whole of the induced dipole moment is due to the outer shell of the electrons. An estimate of the dipole-dipole energy is made using the function u, which in the case of argon gives good agreement with that estimated by other means.