DISPERSION INTERACTIONS BETWEEN EXCITED ATOMS

We present results on the complete dispersion interaction between two neutral multilevel atoms in the same excited state. The calculations i ndicate that the dispersion interaction can produce a repulsive barrie r of the order of congruent-to 7 mueV for intermediate separations and that long-range oscillations exist in the Casimir-Polder regime. The results may be of importance in laser-cooled atomic diffusion phenomen a where translational energies well below this barrier height are achi evable.