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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2004-7-29
pubmed:abstractText
In situ high P-T Raman spectra of solid CO(2) up to 67 GPa and 1,660 K have been measured, using a micro-optical spectroscopy system coupled with a Nd:YLF laser heating system in diamond anvil cells. A metallic foil was employed to efficiently absorb the incoming Nd:YLF laser and heat the sample. The average sample temperature was accurately determined by detailed balance from the anti-Stokes/Stokes ratio, and was compared to the temperature of the absorber determined by fitting the thermal radiation spectrum to the Planck radiation law. The transformation temperature threshold and the transformation dynamics from the molecular phases III and II to the polymeric phase V, previously investigated only by means of temperature quench experiments, was determined at different pressures. The P-T range of the transformation, between 640 and 1,100 K in the 33-65 GPa pressure interval, was assessed to be a kinetic barrier rather than a phase boundary. These findings lead to a new interpretation of the high P-T phase diagram of carbon dioxide. Furthermore, our approach opens a new way to perform quantitative in situ Raman measurements under extremely high pressures and temperatures, providing unique information about phase relations and structural and thermodynamic properties of materials under these conditions.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9606
pubmed:author
pubmed:issnType
Print
pubmed:day
8
pubmed:volume
121
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2780-7
pubmed:year
2004
pubmed:articleTitle
In situ high P-T Raman spectroscopy and laser heating of carbon dioxide.
pubmed:affiliation
Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C. 20015, USA. m.santoro@gl.ciw.edu
pubmed:publicationType
Journal Article