Origin of the complex dielectric relaxation spectra of molecular glass formers

7 págs.; 9 figs. ; PACS number (s): 67.20.1k, 61.12.2q, 61.20.JaThe origin of the three broad bands appearing in the dielectric spectra of molecular glass formers is tracked down to microscopic scales by means of neutron-scattering and molecular-dynamics simulations. Three distinct regimes are also seen in the neutron quasielastic spectrum and are shown to arise from well-separated time regions appearing in the single-particle dipole autocorrelation function derived from simulations. ©2004 American Physical SocietyWork supported in part by Grant No. MAT2002-04540- C05-03 (Spain), the French CNRS, and the U.S. Department of Energy under Contract No. W-31-109-ENG-38.Peer Reviewe