Implementation and Validation of Constrained Density Functional Theory Forces in the CP2K Package.

Constrained density functional theory (CDFT) is a powerful tool for the prediction of electron transfer parameters in condensed phase simulations at a reasonable computational cost. In this work we present an extension to CDFT in the popular mixed Gaussian/plane wave electronic structure package CP2K, implementing the additional force terms arising from a constraint based on Hirshfeld charge partitioning. This improves upon the existing Becke partitioning scheme, which is prone to give unphysical atomic charges.

Electron and Hole Mobilities in Bulk Hematite from Spin-Constrained Density Functional Theory.

Transition metal oxide materials have attracted much attention for photoelectrochemical water splitting, but problems remain, e.g. the sluggish transport of excess charge carriers in these materials, which is not well understood.

Polaronic structure of excess electrons and holes for a series of bulk iron oxides.

Iron oxides such as hematite (α-FeO) play an important role in diverse fields ranging from biogeochemistry to photocatalysis. Here we perform calculations of both the electron and electron hole polaron structures and associated reorganisation energies for a series of bulk iron oxides: hematite (α-FeO), lepidocrocite (γ-FeOOH), goethite (α-FeOOH) and white rust (Fe(OH)). Through the use of gap-optimized hybrid functionals and large supercells under periodic boundary conditions, we remove some of the complications and uncertainties present in earlier cluster model calculations.