Voronoi dipole moments for the simulation of bulk phase vibrational spectra.

We present the Voronoi tessellation of electron density data to obtain molecular dipole moments in bulk phase ab initio molecular dynamics simulations for the calculation of vibrational spectra. Opposed to the established scheme of maximally localized Wannier functions, this approach does not rely on computationally demanding localization procedures. Nevertheless, we show at the examples of methanol, benzene, and phenol that it provides infrared and Raman spectra of similar quality and is even superior in specific cases like the Raman spectra of benzene and phenol. We have also applied the Voronoi method to a mixture of the ionic liquid 1-ethyl-3-methylimidazolium acetate with water, and show that it is advantageous in systems with significant charge transfer.