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Ab initio and molecular dynamics studies of solid β-HMX: effects of hydrostatic pressure and high temperature.
- Source :
- Molecular Simulation; Aug2010, Vol. 36 Issue 9, p670-681, 12p, 1 Diagram, 5 Charts, 7 Graphs
- Publication Year :
- 2010
-
Abstract
- Using first-principles density functional theory and classical molecular dynamics (MD), the structural, electronic and mechanical properties of the energetic material β-HMX have been studied. The crystal structure optimised by the local density approximation calculations compares reasonably with the experimental data. Electronic band structure and density of states indicate that β-HMX is an insulator with a band gap of 3.059 eV. The pressure effect on the crystal structure and physical properties has been investigated in the range of 0-40 GPa. The crystal structure and electronic properties change slightly as the pressure increases from 0 to 2.5 GPa; when the pressure is above 2.5 GPa, further increment of the pressure results in significant changes in crystal structure. There is a larger compression along the b-axis than along the a- and c-axes. Isothermal-isobaric MD simulations on β-HMX were performed in the temperature range of 5-400 K. Phase transition at 360 K, corresponding to a volume interrupt, was found. The computed thermal expansion coefficients show anisotropic behaviour with a slightly larger expansion along the b- and c-axes than along the a-axis. In the temperature range of 5-360 K, β-HMX possesses good plasticity and its stiffness decreases with increasing the temperature. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 08927022
- Volume :
- 36
- Issue :
- 9
- Database :
- Complementary Index
- Journal :
- Molecular Simulation
- Publication Type :
- Academic Journal
- Accession number :
- 52930179
- Full Text :
- https://doi.org/10.1080/08927021003720520