Error Bounds for the Long-Range Forces between Atoms

Abstract

A calculation of the long‐range (van der Waals‐London) forces between atoms is presented. Error bounds on the interaction constant are given when the following properties of the atom are known: (1) the energy of the first excited state, (2) the electron density at the atomic nucleus, (3) the number of electrons in the atom, and (4) the refractive index(polarizability) in the optical region. The error bounds are shown to be the most precise possible, given only the above information. In practice, the accuracy is limited mainly by that of the refractive‐index data. The results for rare‐gas atoms are in agreement with recent molecular‐beam and gas‐kinetic measurements.