Stability and properties of liquid CO2 at high pressure and high temperature: Implications for electrical conductivities in Earth's lower mantle

作者：Wu, Min; Tse, John S.^*; Pan, Yuanming

来源：Geophysical Research Letters, 2015, 42(14): 5820-5827.

DOI：10.1002/2015GL064522

• mantle
• carbon dioxide
• molten structure
• dissociation
• metallization

Carbon dioxide (CO2), one of the most important planetary materials, has been the subject of extensive experimental and theoretical studies. However, the stabilities and properties of CO2 at high pressures and temperatures relevant to Earth's mantle and core remain controversial. We have studied the molten structures of CO2-V with first-principles molecular dynamic calculations at 60GPa and different temperatures. The formation of oxygen molecules in the melt is consistent with experimental observations. In particular, the melting transition is accompanying by metallization. The metallic behavior is shown to originate from electron delocalization between oxygen via the overlap of the orbitals from the dissociated oxygen-rich species. Metallic molten CO2 is a potential candidate to explain the high conductivities of the Earth's lower mantle. Furthermore, theoretical results do not support the existence of the proposed ionic solid phase of CO2 at high temperature and high pressure.

• 出版日期2015-7-28
• 单位浙江工业大学