Identity of the van der Waals force and the Casimir effect and the irrelevance of these phenomena to sonoluminescence

We show that the Casimir, or zero-point, energy of a dilute dielectric ball, or of a spherical bubble in a dielectric medium, coincides with the sum of the van der Waals energies between the molecules that make up the medium. That energy, which is finite and repulsive when self-energy and surface effects are removed, may be unambiguously calculated by either dimensional continuation or by zeta-function regularization. This physical interpretation of the Casimir energy seems to be unambiguous evidence that the bulk self-energy cannot be relevant to sonoluminescence.