Thermodynamic precursors, liquid-liquid transitions, dynamic and topological anomalies in densified liquid germania
- Laboratoire de Physique Théorique de la Matière Condensée, Paris Sorbonne Universités, UPMC, 4 Place Jussieu, F-75252 Paris Cedex 05 (France)
The thermodynamic, dynamic, structural, and rigidity properties of densified liquid germania (GeO{sub 2}) have been investigated using classical molecular dynamics simulation. We construct from a thermodynamic framework an analytical equation of state for the liquid allowing the possible detection of thermodynamic precursors (extrema of the derivatives of the free energy), which usually indicate the possibility of a liquid-liquid transition. It is found that for the present germania system, such precursors and the possible underlying liquid-liquid transition are hidden by the slowing down of the dynamics with decreasing temperature. In this respect, germania behaves quite differently when compared to parent tetrahedral systems such as silica or water. We then detect a diffusivity anomaly (a maximum of diffusion with changing density/volume) that is strongly correlated with changes in coordinated species, and the softening of bond-bending (BB) topological constraints that decrease the liquid rigidity and enhance transport. The diffusivity anomaly is finally substantiated from a Rosenfeld-type scaling law linked to the pair correlation entropy, and to structural relaxation.
- OSTI ID:
- 22493509
- Journal Information:
- Journal of Chemical Physics, Vol. 143, Issue 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
Similar Records
Silica-Encapsulated Germania Colloids as 3D-Printable Glass Precursors
Relationship between the line of density anomaly and the lines of melting, crystallization, cavitation, and liquid spinodal in coarse-grained water models
Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
CORRELATIONS
DENSITY
DIFFUSION
ENTROPY
EQUATIONS OF STATE
FREE ENERGY
GERMANATES
GERMANIUM OXIDES
LIMITING VALUES
LIQUIDS
MOLECULAR DYNAMICS METHOD
PRECURSOR
RELAXATION
SCALING LAWS
SLOWING-DOWN
TEMPERATURE DEPENDENCE
TOPOLOGY
WATER