Global trends of the electric dipole polarizability from shell-model calculations
J. N. Orce, Cebo Ngwetsheni, B. A. Brown
Abstract
Shell-model calculations of the electric dipole ($E1$) polarizability have been performed for the ground state of selected $p$- and $sd$-shell nuclei, substantially advancing previous knowledge. Our results are slightly larger compared with the somewhat more scattered photoabsorption cross-section data, albeit agreeing with ab initio calculations at shell closures and presenting a smooth trend that follows the leptodermous approximation provided by the finite-range droplet model (FRDM). The total $E1$ strengths also show an increasing trend proportional to the mass number which follows from the classical oscillator strength (TRK) sum rule for the $E1$ operator. The enhancement of the energy-weighted sum over $E1$ excitations with respect to the TRK sum rule arises from the use of experimental single-particle energies and the residual particle-hole interaction.