Structure and dynamics in liquid alumina: Simulations with an ab initio interaction potential

Abstract

The atomic structure and dynamics of liquid alumina are studied by molecular dynamics simulation.The interaction potential used accounts for the polarization and deformation of the ions up to a quadrupolar level. The potential is obtained by fitting to the ionic forces and multipoles from ab initio planewave DFT calculations on representative condensed phase ionic configurations. The potential so obtained is transferable and accounts for the phase behaviour and other properties of crystalline Al 2 O 3 as well as its mixtures with other oxides. Here it is shown that the total static and dynamic structure factors for the liquid are in excellent agreement with experiment.

A dipole polarizable potential for reduced and doped CeO2obtained from first principles

“…With such potentials, nanosecond long simulations on thousands of atoms can be performed and these can be used to understand the structural, chemical, mechanical and conducting properties of this material, as previously done for similar systems [22][23][24][25][26][27][28][29][30][31][32]. …”

“…The parameters for these potentials were obtained by matching the forces/dipoles obtained from DIPPIM to first-principles reference data [33]. Such an approach has been applied successfully in the case of other oxide materials [22][23][24][25][26][27][28][29][30][31][32]. In the following we give a brief description of the first-principlesbased reference calculations and the force/dipole-matching procedure.…”

“…Little or no information is provided about the long-or shortdistance behavior where the potential becomes anharmonic. In this paper we use a different methodology, which was used successfully for similar oxide systems [22][23][24][25][26][27][28][29][30][31][32], to parametrize interatomic potentials for stoichiometric, reduced and doped CeO 2 . The key idea of this methodology is that the potential's parameters are fitted to a series of DFT calculations on high temperature, distorted CeO 2 configurations.…”

Atomic dynamics of alumina melt: A molecular dynamics simulation study

“…Hoang and coworkers used a rigid ion model in order to study the self-diffusion [19] and the high pressure behaviour of the melt [20]. An advanced ionic model of AIM-type [21] was recently used to perfectly reproduce both the experimental static and dynamic structure factors of alumina melt [22]. Here, we focus on the relations between the spectra of collective modes, the vibrational spectra and the structural relaxation processes in the melt.…”

Enhancement of nanovoid formation in annealed amorphous Al2O3 including W

“…3(a), Al-O, O-O, and Al-Al peaks can be seen at around 0.18, 0.28, and 0.32 nm, respectively, which is in good agreement with a number of experimental and simulated PDFs of amorphous and liquid Al 2 O 3 . 5,6,[15][16][17][18][19] The PDFs for as-deposited and annealed EB-Al 2 O 3 at 973 and 1073 K are almost consistent with respect to peak intensity and position.…”