Dynasor: Mode projection tutorial data, BaTiO3 MD run

A 1 ns molecular dynamics trajectory of cubic BaTiO3 (Pm-3m, 4x4x4 supercell, 320 atoms) at
500 K, generated with GPUMD using the charge-aware NEP model qnep-mode1-BaTiO-R2SCAN from
Zenodo record 18335947 (https://doi.org/10.5281/zenodo.18335947).

The system was equilibrated for 50 ps in the NVT ensemble with a Langevin thermostat at 500 K
and then propagated for 1 ns in the NVE ensemble, with a time step of 1 fs. Positions and
velocities were written every 5 fs, giving 200 000 snapshots. The cell is fixed and cubic with
a lattice parameter of 4.0 A.

The trajectory is intended for the mode projection dynamics tutorial of dynasor
(https://dynasor.materialsmodeling.org), where it is projected onto selected phonon modes to
obtain mode coordinates, mode momenta, their autocorrelation functions and power spectra.
Velocities are included in the dump, which is what makes the mode momenta accessible.

Files:
  dump.xyz     extended XYZ trajectory, 200 000 frames with positions and velocities (4.6 GB)
  model.xyz    the 4x4x4 supercell used to start the simulation, in GPUMD format
  run.in       the GPUMD input file
  nep.txt      the qNEP potential used
  thermo.out   thermodynamic output, one line per 100 steps
  log_gpumd    GPUMD standard output

Note that the atom ordering in model.xyz matches that of dump.xyz, and mode projection requires
the reference supercell to use the same ordering.

## Keywords

molecular dynamics, phonons, mode projection, perovskite, barium titanate, BaTiO3, GPUMD,
machine-learned interatomic potential, neuroevolution potential, dynasor

## Related identifiers

is supplement to        https://doi.org/10.1016/j.cpc.2025.109759   (dynasor 2 paper)
is derived from         https://doi.org/10.5281/zenodo.18335947     (qNEP model)