Theoretical determination of the Raman spectra of MgSiO3 perovskite and post-perovskite at high pressure

TL;DR

This study uses density functional perturbation theory to predict how Raman spectra of MgSiO3's high-pressure phases evolve, enabling phase identification through Raman spectroscopy.

Contribution

It provides the first theoretical pressure-dependent Raman spectra for MgSiO3 perovskite and post-perovskite, aiding experimental phase detection.

Findings

Three main Raman peaks for perovskite at high pressure

One main Raman peak for post-perovskite at high pressure

Raman spectra differences can indicate phase transition

Abstract

We use the density functional perturbation theory to determine for the first time the pressure evolution of the Raman intensities for a mineral, the two high-pressure structures of MgSiO3 perovskite and post-perovskite. At high pressures, the Raman powder spectra reveals three main peaks for the perovskite structure and one main peak for the post-perovskite structure. Due to the large differences in the spectra of the two phases Raman spectroscopy can be used as a good experimental indication of the phase transition.