دورية أكاديمية
First-Principles Molecular Dynamics Study of Liquid Iron-Rich Alloys Under Conditions of the Earth’s Core
| العنوان: | First-Principles Molecular Dynamics Study of Liquid Iron-Rich Alloys Under Conditions of the Earth’s Core |
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| المؤلفون: | Banjara, Dipendra |
| المصدر: | LSU Doctoral Dissertations |
| بيانات النشر: | LSU Digital Commons |
| سنة النشر: | 2023 |
| المجموعة: | LSU Digital Commons (Louisiana State University) |
| مصطلحات موضوعية: | first-principles, molecular dynamics, iron-rich liquid, diffusion, earth-core, Co Mo W, Earth Sciences, Engineering Science and Materials, Mineral Physics |
| الوصف: | In this dissertation, we report the results of the first-principles molecular dynamics (FPMD) simulations and data analysis on the thermodynamic, structural, and transport properties of iron-rich metallic liquids considering several light and heavy elements under wide ranges of pressure and temperature that are relevant to the earth’s core. Our simulations of pure liquid iron cover the pressure range from 0 GPa at 2000 K to 380 GPa at 7000 K perhaps representing the most extensive computational study to date. We studied four molten iron-rich alloys corresponding to 2.67 atom% of Ni, Co, Mo, and W at pressures up to 380 GPa and at temperatures 4000 to 7000 K. We also simulated H- and C-bearing metallic systems at similar pressure-temperature conditions. The calculated pressure-temperature-volume (P-V-T) results of all liquid alloys can be accurately described with a three-term form of the equation of state consisting of the reference pressure-volume isotherm, the thermal pressure, and the impurity pressure. Moreover, pressure is corrected for the difference in calculation and recent experimental results by adding the fourth term to the equation of state. The resulting density-pressure profile of pure iron liquid along a geotherm shows that the outer core suffers from a density deficient of ~ 6.8%. Our results show that the addition of Mo and W in liquid iron in any amount widens the density gap whereas the addition of H and C reduces the gap. Both Ni and Co do not affect the liquid density significantly and they behave as host iron atoms showing similar bond distances and local coordination. The calculated mean iron coordination number of Mo and W is somewhat larger than that of Ni and Co and host iron atoms thus implying a substitutional incorporation mechanism, whereas both H and C are undercoordinated consistent with their interstitial incorporation. Our results from extended FPMD simulations for pure iron and FeW liquids show that the diffusion coefficient of Fe varies modestly over the outer core regime ... |
| نوع الوثيقة: | text |
| وصف الملف: | application/pdf |
| اللغة: | unknown |
| العلاقة: | https://digitalcommons.lsu.edu/gradschool_dissertations/6041Test; https://digitalcommons.lsu.edu/context/gradschool_dissertations/article/7140/viewcontent/Banjara_diss.pdfTest |
| DOI: | 10.31390/gradschool_dissertations.6041 |
| الإتاحة: | https://doi.org/10.31390/gradschool_dissertations.6041Test https://digitalcommons.lsu.edu/gradschool_dissertations/6041Test https://digitalcommons.lsu.edu/context/gradschool_dissertations/article/7140/viewcontent/Banjara_diss.pdfTest |
| رقم الانضمام: | edsbas.199708F7 |
| قاعدة البيانات: | BASE |
| DOI: | 10.31390/gradschool_dissertations.6041 |
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