An efficient density functional algorithm in a strong magnetic field

We describe the implementation of a manifestly gauge invariant configuration space method for ab initio electronic structure calculations in an arbitrarily strong external magnetic field. To be able to reproduce empirical data for realistic systems, we will also formulate our real-space algorithm in magnetic fields for non-local ionic pseudo- potentials. Numerical applications focus on two issues, namely a careful assessment of the convergence properties of our algorithm and in particular the implications of our gauge invariant formulation, and the calculation of NMR shifts for a number of typical molecules.