| Autor: |
Russell J. Hemley, Yunfeng Liang, Wai-Leung Yim, John S. Tse, Hongliang Shi |
| Rok vydání: |
2017 |
| Předmět: |
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| Zdroj: |
Correlations in Condensed Matter under Extreme Conditions ISBN: 9783319536637 |
| DOI: |
10.1007/978-3-319-53664-4_9 |
| Popis: |
The validity of simple effective oscillator models for extracting band gap energies from frequency-dependent refractive index data of high pressure ice and solid hydrogen was assessed through comparisons of theoretical dielectric response functions obtained from Bethe–Salpeter equation and band gaps calculated from the GW method. For model structures of solid hydrogen, the ‘effective’ band gap trend with pressure estimated from experimental refractive index correlate well with theoretical predictions. However, this is not the case for ice at high pressure . The success in the former can be attributed to the lack of variation in the optical absorption spectral profile with pressure due to the molecular-like localized electronic excitations. In comparison, the width of the absorption band in ice broadened continuously with compression. Single oscillator models are not expected to be reliable when the spectral profile changes significantly with increasing pressure as we predict for dense phases of solid hydrogen , where the molecules exhibit stronger intermolecular interactions than in the lower pressure structures of solid hydrogen. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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