scholarly journals Ice phases under ambient and high pressure: Insights from density functional theory

2013 ◽  
Vol 87 (21) ◽  
Author(s):  
Yuan Fang ◽  
Bing Xiao ◽  
Jianmin Tao ◽  
Jianwei Sun ◽  
John P. Perdew
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Density Functional ◽  
Functional Theory

scholarly journals Compression Behavior and Vibrational Properties of New Energetic Material LLM-105 Analyzed Using the Dispersion-Corrected Density Functional Theory

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6831
Author(s):  
Tianming Li ◽  
Junyu Fan ◽  
Zhuoran Wang ◽  
Hanhan Qi ◽  
Yan Su ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Uniaxial Compression ◽  
Density Functional ◽  
Structural Parameters ◽  
Energetic Material ◽  
Structure Stability ◽  
Vibrational Properties ◽  
Detailed Knowledge ◽  
Functional Theory

The 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) is a newly energetic material with an excellent performance and low sensitivity and has attracted considerable attention. On the basis of the dispersion-corrected density functional theory (DFT-D), the high-pressure responses of vibrational properties, in conjunction with structural properties, are used to understand its intermolecular interactions and anisotropic properties under hydrostatic and uniaxial compressions. At ambient and pressure conditions, the DFT-D scheme could reasonably describe the structural parameters of LLM-105. The hydrogen bond network, resembling a parallelogram shape, links two adjacent molecules and contributes to the structure stability under hydrostatic compression. The anisotropy of LLM-105 is pronounced, especially for Raman spectra under uniaxial compression. Specifically, the red-shifts of modes are obtained for [100] and [010] compressions, which are caused by the pressure-induced enhance of the strength of the hydrogen bonds. Importantly, coupling modes and discontinuous Raman shifts are observed along [010] and [001] compressions, which are related to the intramolecular vibrational redistribution and possible structural transformations under uniaxial compressions. Overall, the detailed knowledge of the high-pressure responses of LLM-105 is established from the atomistic level. Uniaxial compression responses provide useful insights for realistic shock conditions.

scholarly journals Proton dynamics in high-pressure ice-VII from density functional theory

2020 ◽  
Vol 102 (18) ◽  
Author(s):  
Florian Trybel ◽  
Michael Cosacchi ◽  
Thomas Meier ◽  
Vollrath Martin Axt ◽  
Gerd Steinle-Neumann
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Density Functional ◽  
Functional Theory ◽  
Proton Dynamics

A high-pressure study of HfC and nano-crystalline TiC by X-ray diffraction and density functional theory calculations

2020 ◽  
Vol 34 (34) ◽  
pp. 2050393
Author(s):  
Lun Xiong ◽  
Bin Li ◽  
Bi Liang ◽  
Jinxia Zhu ◽  
Hong Yi ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Bulk Modulus ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Nano Crystalline

The equation of state (EOS) of HfC and nanosized TiC at high pressure has been studied by means of synchrotron radiation X-ray diffraction (XRD) in a diamond anvil cell (DAC) at ambient temperature, and density functional theory (DFT) calculations. XRD analysis showed that the cubic structure of HfC and nanosized TiC maintained to the maximum pressures. The XRD data yield a bulk modulus [Formula: see text] GPa with [Formula: see text] of HfC. In addition, the bulk modulus of nanosized TiC derived from XRD data is [Formula: see text] GPa with [Formula: see text].

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