Atomistic Modeling of the Negative Thermal Expansion in δ- Plutonium Based on the Two-State Description
The δ phase of plutonium with the fcc structure exhibits an unusual negative thermal expansion (NTE) over its narrow temperature range of stability, 593–736 K. An accurate description of the anomalous high-temperature volume effect of plutonium goes beyond the current capability of electronic-s...
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| Language: | English |
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MDPI AG
2012-06-01
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| Series: | Materials |
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| Online Access: | http://www.mdpi.com/1996-1944/5/6/1040 |
| _version_ | 1811274870711910400 |
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| author | Steven M. Valone A. C. Lawson Shao Ping Chen Tongsik Lee Michael I. Baskes |
| author_facet | Steven M. Valone A. C. Lawson Shao Ping Chen Tongsik Lee Michael I. Baskes |
| author_sort | Steven M. Valone |
| collection | DOAJ |
| description | The δ phase of plutonium with the fcc structure exhibits an unusual negative thermal expansion (NTE) over its narrow temperature range of stability, 593–736 K. An accurate description of the anomalous high-temperature volume effect of plutonium goes beyond the current capability of electronic-structure calculations. We propose an atomistic scheme to model the thermodynamic properties of δ-Pu based on the two-state model of Weiss for the Invar alloys, inspired by the simple free-energy analysis previously conducted by Lawson<em> et al.</em> The two-state mechanism is incorporated into the atomistic description of a many-body interacting system. Two modified embedded atom method potentials are employed to represent the binding energies of two competing electronic states in δ-Pu. We demonstrate how the NTE takes place in δ-Pu by means of Monte Carlo simulations implemented with the two-state mechanism. |
| first_indexed | 2024-04-12T23:28:01Z |
| format | Article |
| id | doaj.art-3986f47971144af2a4768e9d73aaf8e1 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-04-12T23:28:01Z |
| publishDate | 2012-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-3986f47971144af2a4768e9d73aaf8e12022-12-22T03:12:22ZengMDPI AGMaterials1996-19442012-06-01561040105410.3390/ma5061040Atomistic Modeling of the Negative Thermal Expansion in δ- Plutonium Based on the Two-State DescriptionSteven M. ValoneA. C. LawsonShao Ping ChenTongsik LeeMichael I. BaskesThe δ phase of plutonium with the fcc structure exhibits an unusual negative thermal expansion (NTE) over its narrow temperature range of stability, 593–736 K. An accurate description of the anomalous high-temperature volume effect of plutonium goes beyond the current capability of electronic-structure calculations. We propose an atomistic scheme to model the thermodynamic properties of δ-Pu based on the two-state model of Weiss for the Invar alloys, inspired by the simple free-energy analysis previously conducted by Lawson<em> et al.</em> The two-state mechanism is incorporated into the atomistic description of a many-body interacting system. Two modified embedded atom method potentials are employed to represent the binding energies of two competing electronic states in δ-Pu. We demonstrate how the NTE takes place in δ-Pu by means of Monte Carlo simulations implemented with the two-state mechanism.http://www.mdpi.com/1996-1944/5/6/1040plutoniumnegative thermal expansionInvarWeiss modelmodified embedded atom methodMonte Carlo method |
| spellingShingle | Steven M. Valone A. C. Lawson Shao Ping Chen Tongsik Lee Michael I. Baskes Atomistic Modeling of the Negative Thermal Expansion in δ- Plutonium Based on the Two-State Description Materials plutonium negative thermal expansion Invar Weiss model modified embedded atom method Monte Carlo method |
| title | Atomistic Modeling of the Negative Thermal Expansion in δ- Plutonium Based on the Two-State Description |
| title_full | Atomistic Modeling of the Negative Thermal Expansion in δ- Plutonium Based on the Two-State Description |
| title_fullStr | Atomistic Modeling of the Negative Thermal Expansion in δ- Plutonium Based on the Two-State Description |
| title_full_unstemmed | Atomistic Modeling of the Negative Thermal Expansion in δ- Plutonium Based on the Two-State Description |
| title_short | Atomistic Modeling of the Negative Thermal Expansion in δ- Plutonium Based on the Two-State Description |
| title_sort | atomistic modeling of the negative thermal expansion in δ plutonium based on the two state description |
| topic | plutonium negative thermal expansion Invar Weiss model modified embedded atom method Monte Carlo method |
| url | http://www.mdpi.com/1996-1944/5/6/1040 |
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