Volume 77, Number 4, February 2007
|Number of page(s)||5|
|Section||Condensed Matter: Structural, Mechanical and Thermal Properties|
|Published online||09 February 2007|
Molecular carbon dioxide at high pressure and high temperature
Physique des Milieux Denses, IMPMC, CNRS UMR 7590, Université Pierre et Marie Curie-Paris VI, 140 rue de Lourmel, 75015 Paris, France
2 LENS- via N. Carrara 1, Polo Scientifico - 50019 Sesto Fiorentino (FI), Italy
Accepted: 20 December 2006
The existence of intermediate states between the molecular and non-molecular forms of carbon dioxide has been actively debated in the recent past. Here we report new experiments at pressures up to 20 GPa and in the temperature range 300950 K. They revealed the presence of a previously unobserved molecular phase, which we identified as the theoretically predicted high-temperature Cmca phase. Its relation and relative stability with respect to the other solid phases are discussed based on spectroscopic and melting data. We show that the existence of this strictly molecular phase challenges the interpretation of phases IV and II as intermediate forms between the molecular and covalent-bonded solids.
PACS: 62.50.+p – High-pressure and shock wave effects in solids and liquids / 68.18.Jk – Phase transitions / 78.30.-j – Infrared and Raman spectra
© Europhysics Letters Association, 2007
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.