Mode adiabatique de rotation rapide dans des agrégats de molécules polaires

Strong dipolar interactions have been shown to induce a dipolar solvation effect consisting of orientational order between nearest neighbour molecules and a dynamically coherent effect with spectral density extending over the envelope of molecular free rotations. Here an elementary calculation dealing with a cubic cluster of seven molecules shows the possibility of concerted mode of orientational motion in which the total dipolar interaction energy is significantly negative and is kept constant. This entails the emergence of a coherent mode in the spectral range of free rotations Les interactions dipolaires fortes favorisent l'apparition d'une solvatation dipolaire se manifestant par une mise en ordre orientationnelle et un effet de coherence rotationnelle. Mise en evidence sur un groupe de 7 molecules voisines sur des sites fixes, de l'existence d'un mode orientationnel concerte particulier