A method for the calculation of hyperfine parameters in extended systems under periodic boundary conditions is presented, using the Gaussian and augmented-plane-wave density functional method, and implemented in QUICKSTEP. In order to increase the efficiency in larger systems, a hybrid scheme is proposed, in which an all-electron treatment for the nuclei of interest and a pseudopotential approximation for the remaining atoms in the simulation cell are combined. The method is validated first by comparing the hyperfine parameters for a selection of atoms and small molecules (using a supercell technique) with other theoretical methods and experimental data from literature. As a typical example of a periodic system where our hybrid method can be applied, the hyperfine parameters of the well-characterized R2 L-α-alanine derived radical are evaluated, yielding results in excellent agreement with the available experimental data.
Abstract