Coupled Perturbed Hartree-Fock Calculation of the Static Polarizability for Periodic Systems: Implementation in the CRYSTAL Code

The Coupled Perturbed Hartree‐Fock (CPHF) scheme has been implemented in CRYSTAL06, periodic ab initio computer code that uses a gaussian type basis set, in order to obtain the polarizability of crystalline systems (3D), slabs (2D), polymers (1D) and, as a limiting case, molecules (0D). The formulation is presented, together with applications referring to diamond, silicon and SiC. It turns out that, for a given hamiltonian and basis set, high numerical accuracy can be achieved at relatively low cost compared to the Finite Field perturbation method (FF), that uses a saw‐tooth electric potential. Correctness of the CPHF results was tested with reference to FF calculations with CRYSTAL.