Long-range interaction of two metastable rare-gas atoms

We present semiempirical calculations of long-range van der Waals interactions for two interacting metastable rare-gas atoms Ne through Xe. Dispersion coefficients $C_6$ are obtained for homonuclear molecular potentials asymptotically connecting to the ${\mathrm{ns}(3/2)\mathrm{}}_2{+ns(3/2)\mathrm{}}_2$ atomic states. The estimated uncertainty of the calculated $C_6$ dispersion coefficients is 4%.