Linear potential and phonons in calcium and strontium

The success recently achieved by the linear form of electron-ion pseudopotential in the case of alkalies, Al and Pb has led to further apply it to the bivalent metals, Ca and Sr, for the calculation of phonon propagation along the three symmetry directions. The results obtained compare well with the value based on the more sophisticated formulations of Animalu and Moriarty. The reliability of these results is confirmed through an excellent reproduction of the experimental binding energy and compressibility. A succesful prediction of elastic constants further highlights the usefulness of the present simple approach.