Nuclear polarization in hydrogenlike heavy ions

Abstract

The nuclear polarization (NP) correction is calculated for the ground states of the hydrogenlike ${}_{ 82}^{208}\mathrm{Pb}$ and ${}_{ 92}^{238}\mathrm{U}\mathrm{}$ ions. We take into account the transverse interaction, ignored in the previous studies, as well as the Coulomb interaction. The NP correction is formulated in the bound-state QED formalism with the ladder and cross diagrams of two-photon exchange between an electron and a nucleus. We take into account nuclear excitations of low-lying states and giant resonances with multipolarities of ${\ensuremath{\lambda}}^{\ensuremath{\pi}}{=0}^{+},$ ${1}^{\ensuremath{-}},$ ${2}^{+},$ and ${3}^{\ensuremath{-}},$ and describe them in a collective model. The NP corrections are obtained to be $\ensuremath{-}0.2$ and $\ensuremath{-}180.7$ meV, respectively, for ${}_{ 82}^{208}\mathrm{Pb}$ and ${}_{ 92}^{238}\mathrm{U}.$ The effect of the transverse interaction is found to be essential to the NP correction for electric dipole giant resonances, strongly canceling a contribution of the Coulomb interaction. Dependence of the NP correction on different nuclear excitations is investigated.