Details

Autor(en) / Beteiligte

• Zürcher, U
• Keyes, T

Titel

Configurational entropy and collective modes in normal and supercooled liquids

Ist Teil von

• Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 1999-08, Vol.60 (2 Pt B), p.2065-2070

Ort / Verlag

United States

Erscheinungsjahr

1999

Quelle

PROLA - Physical Review Online Archive

Beschreibungen/Notizen

• Soft vibrational modes have been used to explain anomalous thermal properties of glasses above 1 K. The soft-potential model consists of a collection of double-well potentials that are distorted by a linear term representing local stress in the liquid. Double-well modes contribute to the configurational entropy of the system. Based on the Adam-Gibbs theory of entropically driven relaxation in liquids, we show that the presence of stress drives the transition from Arrhenius to Zwanzig-Bässler temperature dependence of relaxation times. At some temperature below the glass transition, the energy scale is dominated by local stress, and soft modes are described by single wells only. It follows that the configurational entropy vanishes, in agreement with the "Kauzmann paradox." We discuss a possible connection between soft vibrational modes and ultrafast processes that dominate liquid dynamics near the glass transition.