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Ab initio calculations of the structural and dynamical properties of copper pyrophosphate
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1  Institute of Nuclear Physics Polish Academy of Sciences

Published: 11 November 2020 by MDPI in 2nd International Online-Conference on Nanomaterials session Poster

Pyrophosphate nanocomposite materials containing transition metal ions have unique physical, chemical, electrical and mechanical properties . Especially interesting characteristics show compounds containing cooper atoms, which have received a lot of attention in research and application due to its excellent conductivity as well as good biocompatibility and increased surface Raman scattering activity (SERS). In our research, we apply the density functional theory and lattice dynamics calculations to get a better insight into the structural and dynamic properties of the Cu2P2O7 crystal. Copper pyrophosphate has a monoclinic crystal structure described by the C2/c (15) space group and lattice parameters: a=6.901 Å, b=8.108 Å, c=9.176 Å, β = 109.65o. All calculations were performed with the Vienna Ab initio Simulation Package (VASP) within the general gradient approximation (GGA). The stability of the crystal structure was tested by determining the phonon dispersion relations and the phonon density of states (PDOS) using the PHONON program based on the direct method . In the optimized structure all non-equivalent atoms were shifted from equilibrium positions and Hellmann-Feynman (HF) forces acting on all atoms were calculated.

The obtained results were compared with the experimental measurements of nanocrystalline copper pyrophosphates. The comparison of theoretically determined Raman scattering spectra with the experimental data enables the identification of the crystalline phases of pyrophosphates.

Keywords: Pyrophosphate, ab initio, numerical calculations, Raman