Dielectric susceptibility of liquid water: Microscopic insights from coherent and incoherent neutron scattering

The analysis of neutron scattering results on H dynamics (H2O) and the dynamic structure factor (D2O) around the intermolecular peak and at intermediate length scales in terms of the susceptibilities reveals three processes (diffusive, local relaxational and vibrational) at frequencies below 3 THz, to which the contributions commonly invoked in dielectric studies can be directly mapped. We achieve a unified description of the results from both techniques, clarifying the nature of the molecular motions involved in the dielectric spectra and their impact on the structural relaxation.Financial support by the Spanish Ministry ’Ministerio de Economia y Competitividad, code: MAT2015-63704-P (MINECO/FEDER, UE) and by the Eusko Jaurlaritza (Basque Government), code: IT-654-13 is acknowledged.Peer reviewe