New insights into the melting behavior of MgO from molecular dynamics simulations: the importance of premelting effects.
We provide a plausible resolution of a long-standing controversy relevant to the geophysics community, namely, that the experimental slope of the melting curve Tm(P) of MgO at low pressures is about 3 times smaller than that obtained from computer simulation of the melting of the normal rock-salt-st...
Main Authors: | , |
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Format: | Journal article |
Language: | English |
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2005
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author | Aguado, A Madden, P |
author_facet | Aguado, A Madden, P |
author_sort | Aguado, A |
collection | OXFORD |
description | We provide a plausible resolution of a long-standing controversy relevant to the geophysics community, namely, that the experimental slope of the melting curve Tm(P) of MgO at low pressures is about 3 times smaller than that obtained from computer simulation of the melting of the normal rock-salt-structured crystal. With increasing temperature at zero pressure, our simulations predict a solid-solid phase transition (from a rock salt to a wurtzite crystalline lattice) to occur just before melting. The coexistence of wurtzite and liquid phases at low pressures is found to be described by a Clapeyron slope which is in much better agreement with the experimental results of Zerr and Boehler [Nature (London) 371, 506 (1994)] than the calculated melting line for the rock salt structure. We also show that the existence of a certain concentration of lattice defects in the rock salt phase cannot provide an alternative explanation. |
first_indexed | 2024-03-06T18:06:28Z |
format | Journal article |
id | oxford-uuid:0195d6ba-b008-4aed-9dd2-12ddd0d05ad5 |
institution | University of Oxford |
language | English |
last_indexed | 2024-03-06T18:06:28Z |
publishDate | 2005 |
record_format | dspace |
spelling | oxford-uuid:0195d6ba-b008-4aed-9dd2-12ddd0d05ad52022-03-26T08:35:52ZNew insights into the melting behavior of MgO from molecular dynamics simulations: the importance of premelting effects.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:0195d6ba-b008-4aed-9dd2-12ddd0d05ad5EnglishSymplectic Elements at Oxford2005Aguado, AMadden, PWe provide a plausible resolution of a long-standing controversy relevant to the geophysics community, namely, that the experimental slope of the melting curve Tm(P) of MgO at low pressures is about 3 times smaller than that obtained from computer simulation of the melting of the normal rock-salt-structured crystal. With increasing temperature at zero pressure, our simulations predict a solid-solid phase transition (from a rock salt to a wurtzite crystalline lattice) to occur just before melting. The coexistence of wurtzite and liquid phases at low pressures is found to be described by a Clapeyron slope which is in much better agreement with the experimental results of Zerr and Boehler [Nature (London) 371, 506 (1994)] than the calculated melting line for the rock salt structure. We also show that the existence of a certain concentration of lattice defects in the rock salt phase cannot provide an alternative explanation. |
spellingShingle | Aguado, A Madden, P New insights into the melting behavior of MgO from molecular dynamics simulations: the importance of premelting effects. |
title | New insights into the melting behavior of MgO from molecular dynamics simulations: the importance of premelting effects. |
title_full | New insights into the melting behavior of MgO from molecular dynamics simulations: the importance of premelting effects. |
title_fullStr | New insights into the melting behavior of MgO from molecular dynamics simulations: the importance of premelting effects. |
title_full_unstemmed | New insights into the melting behavior of MgO from molecular dynamics simulations: the importance of premelting effects. |
title_short | New insights into the melting behavior of MgO from molecular dynamics simulations: the importance of premelting effects. |
title_sort | new insights into the melting behavior of mgo from molecular dynamics simulations the importance of premelting effects |
work_keys_str_mv | AT aguadoa newinsightsintothemeltingbehaviorofmgofrommoleculardynamicssimulationstheimportanceofpremeltingeffects AT maddenp newinsightsintothemeltingbehaviorofmgofrommoleculardynamicssimulationstheimportanceofpremeltingeffects |