Employment of curvilinear coordinates in ab initio calculations of insulators using pseudopotentials

The standard ab initio scheme for calculating the structure of crystals using nonlocal pseudopotentials is modified for use in curvilinear coordinates. A method for solving the Poisson equation for the Coulomb potential in a curved space in the k representation is found. It is shown in the example of calculations for crystals of insulators having an NaCl structure that the employment of a curved space permits a very significant decrease in the required size of the basis set. Fiz. Tverd. Tela (St. Petersburg) 41, 241–246 (February 1999)