Using density functional theory to increase the accuracy of experimental crystal structures: The case of potassium peroxocarbonate

摘要: Abstract A first principles simulation of the crystal structure potassium peroxocarbonate is presented, using density functional methods (both local and semilocal) for calculations. An experimental with a seemingly inconsistent disposition peroxide bonds was used as initial input. Both geometry optimizations molecular optimization cell size were performed. While parameters heavier atom positions determined at GGA level are very close to ones, there important discrepancies in positioning hydrogen atoms. As result these calculations, it shown that assignment peroxydic hydrogens bond incorrect. more accurate presented geometrical well described. It also LDA not enough describe this type ionic crystals, because overbinding ions, leading incorrect volume. Our methodology validated DFT several basis sets.