ab initio simulations. The freely available CP2k software package was used for all simulations, which made use of three-dimensional periodic boundary conditions. The Perdew-Burke-Ernzerhof (PBE) density functional coupled with the dispersion correction of Grimme (Grimme-D3 ) and all atoms were represented using the double-zeta DZVP basis set. AIMD simulations were performed within the isobaric-isothermal (NPT) and canonical ensemble (NVT), with the temperature maintained at 300 K using a Nose-Hoover chain thermostat. The initial structure was based off the previously published experimental X-ray diffraction structure, with hydrogen positions added where appropriate. The NPT simulations were performed using a timestep of 1 fs, and were equilibrated for 20 ps prior to performing the NVT simulations. The NVT simulations were performed using a timestep of 0.5 fs, and were equilibrated for 5 ps prior to performing the production run for 30 ps (35 ps total). The molecular dipole moments were determined by calculating localized Wannier functions every 2.5 ps, and the resulting IR spectra for the simulation determined by taking the Fourier transform of the dipole moment autocorrelation function using the Travis postprocessing software, as previously described. The final structure (averaged from the last 500 fs of the AIMD simulations) was used to initialize geometry optimizations, which were performed with a fixed unit cell. Static frequencies were determined within the harmonic approximation by numerical differentiation.