Atomic positions of amorphous tantala models

This repository contains atomic positions data of three model structures of amorphous tantala (a-Ta2O5) that were generated by quench from the melt procedure by means of combined usage of classical and ab-initio molecular dynamics (Models I and II), and fully via ab-initio molecular dynamics (Models III), and subsequently were used for a series of ab-initio calculations of the vibrational spectra, i.e. vibrational density of states (VDOS), infrared and Raman spectra, as explained in details in the paper: L. Giacomazzi and P. Umari,"Vibrational spectra of a-Ta2O5: a first-principles investigation" ,to be published in Physical Review Materials (Accepted for publication on 7th August 2026). Configurations are provided using the xsf (XCrysden) format for structure files with positions and cell sides specified in Angstrom. Trieste 17.8.2026Luigi Giacomazzi (CNR-IOM) --------------------------- Files description: 1) model_I_ta2o5.xsf: The atomic structure of the bulk a-Ta2O5 model labelled as Model I in the Phys. Rev. Mater. (2026) paper. This model contains 336 atoms, with the lattice parameters of 14.46450, 15.37350, 19.35522 Angstrom in the x, y and z direction, respectively. 2) model_II_ta2o5.xsf: The atomic structure of the bulk a-Ta2O5 model labelled as Model II in the Phys. Rev. Mater. (2026) paper. This model contains 126 atoms, with the lattice parameters of 10.87027, 11.55338, 12.92948 Angstrom in the x, y and z direction, respectively. 3) model_III_ta2o5.xsf: The atomic structure of the bulk a-Ta2O5 model labelled as Model III in the Phys. Rev. Mater. (2026) paper. This model contains 126 atoms, with the lattice parameters of 12.07614, 12.07614, 12.07614 Angstrom in the x, y and z direction, respectively.