MOLECULAR DYNAMICS STUDY OF THE FORMATION OF SPECULAR HEMATITE FROM NANOPARTICLES

Nanoparticle aggregates of specular hematite with thermal emission spectra similar to those of Martian hematites were recently produced at low temperature via synthesis in suspension and subsequent freeze-drying (Madden et al., 2010, Earth and Planetary Science Letters, 298, 377-384). During this process, platy hematite nanoparticles become crystallographically aligned, and we hypothesize that this occurs during the freezing process. To test this hypothesis, we are performing molecular dynamics simulations to track the alignment of hematite nanoparticles of different shapes, and interstitial water ordering, in suspension and during freezing. Our results may give some insights about how specular hematite might have formed on Mars at low temperatures.