Session X16 - Structural Phase Transitions.
ORAL session, Thursday afternoon, March 15
Room 303, Washington State Convention Center
Molecular dynamics (MD) simulations, based on our charge-transfer potential, were used to simulate the phase transformation between alpha- and beta-cristobalite.* These simulations reveal the detailed transformation mechanism, in particular spatial correlations between transformed entities during incubation and progression of the transition. The transformation characteristics differ, depending on whether the transition is induced thermally or mechanically. The negative thermal expansion coefficient of beta-cristobalite has intriguing implications on the reverse transformation and the melting behavior of this substance. A better understanding of the thermo-mechanical anomalies of crystalline and amorphous silica is derived from careful analysis of the simulated atomic trajectories.
* L. Duffrène and J. Kieffer, "Molecular Dynamic Simulations of the alpha-beta Phase Transition in Silica Cristobalite," J. Phys. Chem. Solids 59, 1025-1037 (1998)