  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 photo-absorption cross-section data,
albeit agreeing with ab initio calculations at shell closures and presenting a
smooth trend that follows the leptodermus 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.
