Kyohei Takae (Institute of Industrial Science, University of Tokyo), présentera un séminaire le 25 janvier 2016 à 11h dans la bibliothèque du laboratoire PHENIX (7e étage, bâtiment F, porte 754) intitulé :
Fluctuations of local electric field and dipole moments in water between metal walls
Résumé
We examine the thermal fluctuations of local electric field and dipole moments in liquid water between parallel metal walls. In this geometry, fluctuation of the perpendicular component of the total polarization
is suppressed because of the global coupling between the total polarization and the charge of the metal walls. Spatial correlation of the polarization density perpendicular to the walls contains a homogeneous term inversely proportional to the cell volume, thus, the polarization fluctuation is highly anisotropic, particularly in small systems. We also discuss the relationship between macroscopic electric field and local electric field exerted on each molecule, where the latter is considerably larger than the former. The orientation of water dipole is almost parallel to the local electric field,
and small fluctuation is relaxed by the librational motions.
