Density-functional tight-binding parameters for bulk zirconium: A case study for repulsive potentials

Aulia Sukma Hutama, Chien Pin Chou, Yoshifumi Nishimura, Henryk A. Witek, Stephan Irle

研究成果: Article査読

抄録

Density-functional tight-binding (DFTB) parameters are presented for the simulation of the bulk phases of zirconium. Electronic parameters were obtained using a band structure fitting strategy, while two-center repulsive potentials were created by particle swarm optimization. As objective functions for the repulsive potential fitting, we employed the Birch−Murnaghan equations of state for hexagonal close-packed (HCP), body-centered cubic (BCC) and ω phases of Zr from density-functional theory (DFT). When fractional atomic coordinates are not allowed to change in the generation of the equation-of-state curves, long-range repulsive DFTB potentials are able to almost perfectly reproduce equilibrium structures, relative DFT energies of the bulk phases, and bulk moduli. However, the same potentials lead to artifacts in the DFTB potential energy surfaces when atom positions in the unit cell are allowed to fully relax during the change of unit cell parameters. Conventional short-range repulsive DFTB potentials, while inferior in their ability to reproduce DFT bulk energetics, are able to correctly reproduce the qualitative shape of the DFT potential energy surfaces, including the location of global minima, and can therefore be considered more transferable.

本文言語English
ページ(範囲)2184-2196
ページ数13
ジャーナルJournal of Physical Chemistry A
125
10
DOI
出版ステータスPublished - 2021 3 18

ASJC Scopus subject areas

  • 物理化学および理論化学

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