Nonlocal pseudopotential formulation for lattice dynamics

Lattice dynamics of simple metals is formulated using the pseudopotential method with a nonlocal pseudopotential. The core wave functions needed in the pseudopotential are required to satisfy the boundary conditions on the atomic cell. The screening effects due to conduction electrons are treated in Hartree approximation and a simple approach is also suggested to incorporate exchange and correlation effects. Explicit expressions are obtained for phonon frequencies