2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/17033We present the theory of analytical Hartree-Fock gradients for periodic systems as implemented in the code CRYSTAL. We demonstrate how derivatives of the integrals can be computed with the McMurchie-Davidson algorithm. Highly accurate gradients with respect to nuclear coordinates are obtained for systems periodic in 0,1,2 or 3 dimensions.accepted by International Journal of Quantum ChemistryMaterials Sciencetext