RepOD

Raman folder:

Raman spectra were measured on a WITec Alpha300M+ Raman imaging microscope. A 532 or 633 nm laser line was delivered to the microscope via a single-mode optical fiber, with the laser power at the sample not exceeding 25 mW. The Raman signal was collected through a 50× long working distance objective (NA = 0.40) and transmitted through a photonic crystal fiber to a lens-based spectrometer (Witec UHTS 300, f/4 aperture, focal length 300 mm) equipped with a back‑illuminated Andor iDUS 401 detector, which was thermoelectrically cooled to −60 °C. The spectra were acquired using an 1800 mm⁻¹ grating, resulting in a spectral resolution of 1.2 cm⁻¹ or better. Typical acquisition was done from a 12 × 12 μm² area with a 6 × 6 sampling (2 μm spatial resolution). The 36 resulting spectra obtained from the area scan were postprocessed using the Project FIVE software (Witec Gmbh) by performing background subtraction and cosmic ray removal and then averaged into a single spectrum.

 Description of files (ASCII format):

- spectra_compr.dat – normalized spectra obtained upon compression (Raman shift in cm^–1 in first column, pressure given in the header of each column

- spectra_decompr.dat – normalized spectra obtained upon decompression (Raman shift in cm^–1 in first column, pressure given in the header of each column

- freq.dat – position of Raman bands (in cm^–1) obtained by fitting the Raman spectrum obtained upon compression with pseudo-Voigt profiles (pressure in GPa in first column)

PXRD folder:

High pressure powder X-ray diffraction (PXRD) measurements were performed at the DanMAX beamline at the MAX IV synchrotron (λ = 0.3542 Å, beam size ∼19 × 15 µm²) with NaCl acting as a pressure calibrant. Diffractograms were recorded on a Dectris Pilatus3 X 2M CdTe area detector calibrated with a Si standard. All 2D diffractograms were integrated using the Dioptas software.

Description of files (ASCII format):

- Si_calibration.poni – detector calibration file

- [pressure in kbar].xy – integrated powder x-ray diffraction profile at a given pressure

DFT folder:

Input files and results of Density Functional Theory (DFT) modelling (geometry optimization and Raman spectrum calculations) performed in VASP 6.3.4 code for four polymorphs of PdF₃ (results for each structure in separate folders). Calculations performed using the HSE06 method. Force-sets used for vibrational properties calculations contained in separate subfolder.

Calculation parameters: 700 eV cutoff of the plane-wave basis set; PAW pseudopotentials; SCF convergence: 10^–7 eV per atom; k-point mesh with a 2π × 0.05 Å⁻¹ spacing.

Description of files (ASCII format):

INCAR – file containing VASP-specific commands

KPOINTS – k-point sampling

POTCAR – PAW pseudopotential file

PdF3-[symmetry tag]-[pressure in kbar].vasp – structure optimized at a given pressure given in VASP format

FORCE_SETS_[pressure in GPa] – force sets at a given pressure