Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 66: Frontiers of Electronic Structure Theory: Focus on Topology and Transport

O 66.1: Poster

Mittwoch, 9. März 2016, 18:15–20:30, Poster A

Improving anharmonic vibrational calculations from first principles — •Joseph C.A. Prentice, Bartomeu Monserrat, and Richard J. Needs — TCM Group, Cavendish Laboratory, University of Cambridge, UK

The vibrational self-consistent field (VSCF) method, as described in PRB 87 144302, has had several successes in accurately calculating the anharmonic properties of various materials, such as diamond, ice and solid hydrogen. However, a practical issue with the method is the large number of DFT calculations required to map the Born-Oppenheimer energy surface sufficiently accurately. We look at improvements to the method that reduce this computational load, in particular using data on forces from DFT calculations to improve the accuracy of the mapping. Results using this improved method are presented for competing structures of silicate perovskite under lower mantle conditions. Further improvements, involving the inclusion of n-body coupling between phonons, and their possible implementation are also discussed.