Data to "Anisotropic phonon bands in H-bonded molecular crystals: the instructive case of alpha-quinacridone"

Simulation data to the article "Anisotropic phonon bands in H-bonded molecular crystals: the instructive case of alpha-quinacridone"

The data comprises structure relaxations and atomic force calculations from first principle within dispersion-corrected density-functional theory.

1-molecular_vibrations.zip contains:

1. structure relaxation of the isolated quinacridone molecule. For the structure used in the periodic Finite Difference Scheme calculations we simply added the three lattice vector lines at the top.
2. periodic force calculations to deduce the molecular vibrations with Phonopy
3. analogous non-periodic calculations to verify the periodic approach.

2-phonons.zip

1. Gamma-point phonons deduced from a primitive cell of alpha-quinacridone, a crystalline phase of the quinacridone molecule.
2. Calculated force constants to access the phonon properties in the entire Brillouin zone, including calculating the phonon band structure.

Supporting_Information.zip contains:

1. Structure relaxations for three quinacridone polymorphs for comparison with experimental O...H-N bonding distances with the Generalized Gradient Approximation functional PBE and in part the hybrid functional PBE0
2. Convergence test for the employed k-space sampling (k-grid) and number of basis function for the structure code FHI-aims, comparing both total energies and Gamma-point phonons for alpha-quinacridone.
3. Phonon band structure calculation of alpha-quinacridone with the structure code VASP, using the Grimme D3BJ van der Waals correction (which is not available in standard FHI-aims).
4. Phonon calculations for different super cell sizes for the sake of convergence tests.
5. Several calculations to estimate the influence of anharmonicity on the phonon properties. This includes i.) varying Phonopy's displacement amplitude until leaving the linear response regime, ii.) comparing Gamma-point phonons for the structure with experimental and fully-relaxed unit cells, and iii.) energies of structures displaced along vibrational eigenmodes.