First-Principles Calculations of Phonons and Thermodynamic Properties of Zr(Hf)S2 -Based Nanotubes
© 2019 Wiley Periodicals, Inc.
| Veröffentlicht in: | Journal of computational chemistry. - 1984. - 41(2020), 8 vom: 30. März, Seite 759-768 |
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| Weitere Verfasser: | , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2020
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| Zugriff auf das übergeordnete Werk: | Journal of computational chemistry |
| Schlagworte: | Journal Article Helmholtz energy entropy hafnium disulfide heat capacity monolayers phonon dispersion phonon frequencies single-walled nanotubes strain energy |
| Zusammenfassung: | © 2019 Wiley Periodicals, Inc. Comparative hybrid density functional calculations on the structure, stability, and phonon frequencies of monolayers and single-walled nanotubes are performed for Zr(Hf)S2 disulfides. The first-principles calculations of HfS2 -based nanotubes are made for the first time. The symmetry analysis of infrared and Raman active vibrational modes in ZrS2 and HfS2 nanotubes is made using the induced representations of the isogonal point groups of line groups. It is shown that the number of infrared and Raman active modes is constant for NTs with the same chirality type. The correlation of the phonon modes of the nanotubes of relatively large diameters with those of monolayer is analyzed. The thermodynamic functions of monolayers and nanotubes with various chirality and diameters are calculated on the basis of the obtained phonon frequencies. It is established that the phonon contribution to the nanotube strain energy is small, but may be important for an accurate estimate of the stability of the nanotubes of small diameters. The calculated results show that the thermal contributions to Helmholtz free energy are positive; thereby they slightly reduce the stability of ZrS2 and HfS2 nanotubes at elevated temperatures. © 2019 Wiley Periodicals, Inc |
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| Beschreibung: | Date Revised 12.02.2020 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1096-987X |
| DOI: | 10.1002/jcc.26124 |