Dispersion forces

Abstract

The interaction energy between two atoms is calculated including radiative corrections. It is shown that the interaction energy can be expressed in terms of the frequency-dependent polarizability and this leads to some simple approximate methods for the calculation of this energy. Magnetic dipole terms are also included and these terms are found to give a difference in the dispersion energy between two optically active molecules depending on whether they have identical or mirror image configurations. They may also be important for molecules with low-lying magnetic excited states.