A geminal model for the electronic structures of extended systems

Electronic structure methods for extended systems based on the local one-electron states have a great potential for the correlated treatment of polymers and solids. In this article, we propose a variational ab initio method for electronic structure of semiconductors based on the local geminal wave function with periodic boundary conditions. The implementation does not require transformation of two-electron integrals from atomic to molecular orbital basis, which makes the method computationally efficient. The method performance is illustrated on the example of one-dimensional systems: hydrogen, carbon, and LiH chains. Special attention is given to the energy convergence, dependence of energy on the geometry parameters, structure of local one-electron states, and bonding properties.