Phase transitions of enstatite MgSiO 3 : a molecular dynamics study

Autor: S. L. Chaplot, Narayani Choudhury
Rok vydání: 2000
Předmět:
Zdroj: Solid State Communications. 116:599-603
ISSN: 0038-1098
DOI: 10.1016/s0038-1098(00)00392-6
Popis: Molecular dynamics simulations as a function of increasing pressure starting from the Earth's upper mantle phase enstatite MgSiO3 reveal successive phase transitions, first to a new novel intermediate phase, and then to the lower-mantle perovskite phase. While the silicate units are in tetrahedral coordination in the enstatite phase, they are five-coordinated in the new intermediate phase and in octahedral coordination in the lower mantle perovskite phase. Although the occurrence of crystalline five-coordinated silicate phases is somewhat rare, the new intermediate phase obtained through the simulations is found to be crystalline. The simulations have enabled a microscopic visualization of the key mechanisms of these transitions and provide useful insights about the variations in the vibrational properties due to these changes in silicate coordination.
Databáze: OpenAIRE