Europhys. Lett.
Volume 76, Number 5, December 2006
Page(s) 836 - 841
Section Condensed matter: structural, mechanical and thermal properties
Published online 01 November 2006
Europhys. Lett., 76 (5), pp. 836-841 (2006)
DOI: 10.1209/epl/i2006-10347-6

A dynamic pathway for the alkaline earth oxides B1 to B2 transformation

R. C. Mota, P. S. Branício and J. P. Rino

Departamento de Física, Universidade Federal de São Carlos São Carlos, SP 13565-905, Brazil

received 17 August 2006; accepted in final form 3 October 2006
published online 1 November 2006

The rocksalt (B1) to CsCl (B2) pressure-induced structural transformation in CaO is investigated with isenthalpic-isobaric molecular dynamics simulations. The analysis of the dynamic transformation reveals an atomic mechanism following a pathway formed by a combination of three mechanisms proposed independently. The transformation starts with a Buerger $R\bar {3}m$ deformation of the B1 structure that is followed by the Stokes P21/m mechanism leading to an intermediate B33 monoclinic phase, which then connects to the B2 phase by using the Tolédano Pbcm pathway. This unexpected dynamic mechanism may help to evaluate the lifetime of the intermediate states and the kinetics in the B1 to B2 transformation in these whole set of Earth crust materials.

61.43.Bn - Structural modeling: serial-addition models, computer simulation.
62.50.+p - High-pressure and shock wave effects in solids and liquids.
64.70.Kb - Solid-solid transitions.

© EDP Sciences 2006