Nonperturbative effect of attractive forces in viscous liquids

Ludovic Berthier (1) , Gilles Tarjus (2)

1 LCVN - Laboratoire des colloïdes, verres et nanomatériaux
2 LPTMC - Laboratoire de Physique Théorique de la Matière Condensée

We study the role of the attractive intermolecular forces in the viscous regime of a simple glass-forming liquid by using computer simulations. To this end, we compare the structure and the dynamics of a standard Lennard-Jones glass-forming liquid model with and without the attractive tail of the interaction potentials. The viscous slowing down of the two systems are found to be quantitatively and qualitatively different over a broad density range, whereas the static pair correlations remain close. The common assumption that the behaviour of dense nonassociated liquids is determined by the short-ranged repulsive part of the intermolecular potentials dramatically breaks down for the relaxation in the viscous liquid regime.

Domaines: Mécanique statistique [cond-mat.stat-mech]; Systèmes désordonnés et réseaux de neurones [cond-mat.dis-nn]

Ludovic Berthier, Gilles Tarjus. Nonperturbative effect of attractive forces in viscous liquids. Physical Review Letters, 2009, 103, pp.170601. ⟨10.1103/PhysRevLett.103.170601⟩. ⟨hal-00522293⟩