LONG-RANGE INTERACTIONS OF SODIUM ATOMS

Long-range interaction potentials between two and three sodium atoms, between a sodium atom and a perfectly conducting wall, and for a sodiu m atom between two perfectly conducting walls, are calculated with an electric-dipole oscillator strength distribution constructed from comb inations of experimental and theoretical energy levels, oscillator str engths, and photoionization cross section data, constrained by accurat e values of oscillator strength sum rules. The leading dispersion coef ficients for Na-Na and Na-Na-Na and the Lennard-Jones coefficient for the Na-wall system are determined. For Na-Na and for the Na-wall syste ms, the retarded (Casimir) potentials are also calculated.