Low-Scaling Local and Fragment Self-Consistent Field Potentials in Molecular Systems

Due to the steep scaling of computational cost with increasing system size in self-consistent field calculations, approximations are required in order to make biomolecular applications amenable. Two approaches are presented and compared with this purpose in mind. On the one hand we have fragment approaches which split the system into smaller entities. The coupling can be included with varying accuracy. On the other hand, local density fitting approximations which exploit the physics of exchange contributions. These methods provide manifold applications such as the analysis of embedding schemes for QM/MM calculations or the linear scaling of hybrid density functionals. In the selectivity analysis of a cyanobacterial enzyme the use of local potentials could rule out electronic structure contributions as a steering factor and moved steric shielding into the focus of investigation