Bulk properties and near-critical behaviour of SiO2 fluid
Eleanor CR Green, Emilio Artacho, James AD Connolly
EARTH AND PLANETARY SCIENCE LETTERS | ELSEVIER SCIENCE BV | Published : 2018
Rocky planets and satellites form through impact and accretion processes that often involve silicate fluids at extreme temperatures. First-principles molecular dynamics (FPMD) simulations have been used to investigate the bulk thermodynamic properties of SiO2 fluid at high temperatures (4000–6000 K) and low densities (500–2240 kg m−3), conditions which are relevant to protoplanetary disc condensation. Liquid SiO2 is highly networked at the upper end of this density range, but depolymerises with increasing temperature and volume, in a process characterised by the formation of oxygen–oxygen (O[dbnd]O) pairs. The onset of vaporisation is closely associated with the depolymerisation process, and..View full abstract
Awarded by Swiss National Science Foundation
We are grateful to Felipe Gonzalez-Cataldo for sharing his unpublished data with us, and to Oliver Strickson for allowing us to use his driver for the SIESTA code. E.C.R. Green thanks the Theory Group at CIC nanoGUNE, San Sebastian, Spain, for their hospitality, and particularly Fabiano Corsetti for his careful explanations. The valuable comments of two anonymous reviewers and the editorial handing of Prof Frederic Moynier are gratefully acknowledged. This work was supported by the Swiss National Science Foundation [grant numbers 2-77675-13 and 2-77177-15].