Brueckner-Goldstone Many-Body Theory for Dynamic Polarizabilities: Application to Ne

A many-body procedure applied earlier to helium is utilized here to study the response of a neon atom in its ground state to a time-dependent electric field. The theory of the method, omitted in the helium paper for reasons of brevity, is included here. Our results for the frequency-dependent polarizabilities $\alpha \left(\omega \right)$ lead to refractive indices $n\left(\omega \right)$, in excellent agreement with experiment. As a by-product of the calculation, we obtain [from the poles of $\alpha \left(\omega \right)$] excitation energies for $2p\to \mathrm{ns}$ and $2p\to \mathrm{nd}$ transitions in good agreement with experiment.