Transition rates of atoms near spherical surfaces

We study the transition rates of atoms inside and outside dielectric spheres. The rates are calculated classically, and the results are shown to agree with those obtained using other approaches. For atoms outside, our analytic results are equivalent to those of Ruppin in the case of zero conductivity. Numerical results are presented, which show that resonances have important effects on the transition rates, and that enhancement factors of hundreds are possible under suitable conditions.