scholarly journals Transformation pathways in high-pressure solid nitrogen: From molecular N2 to polymeric cg-N

2015 ◽  
Vol 142 (9) ◽  
pp. 094505 ◽  
Author(s):  
Dušan Plašienka ◽  
Roman Martoňák
Keyword(s):  
High Pressure ◽  
Solid Nitrogen ◽  
Transformation Pathways

High-pressure static and dynamic properties of theR3¯cphase of solid nitrogen

1986 ◽  
Vol 33 (12) ◽  
pp. 8615-8621 ◽  
Author(s):  
R. D. Etters ◽  
V. Chandrasekharan ◽  
E. Uzan ◽  
K. Kobashi
Keyword(s):  
High Pressure ◽  
Dynamic Properties ◽  
Solid Nitrogen

A high-pressure van der Waals compound in solid nitrogen-helium mixtures

Nature ◽  
1992 ◽  
Vol 358 (6381) ◽  
pp. 46-48 ◽  
Author(s):  
W. L. Vos ◽  
L. W. Finger ◽  
R. J. Hemley ◽  
J. Z. Hu ◽  
H. K. Mao ◽  
...  
Keyword(s):  
High Pressure ◽  
Van Der Waals ◽  
Helium Mixtures ◽  
Solid Nitrogen

scholarly journals Solubility of fluid helium in solid nitrogen at high pressure

1990 ◽  
Vol 64 (8) ◽  
pp. 898-901 ◽  
Author(s):  
Willem Vos ◽  
Jan Schouten
Keyword(s):  
High Pressure ◽  
Solid Nitrogen

scholarly journals Stability limits and transformation pathways ofα-quartz under high pressure

2017 ◽  
Vol 95 (10) ◽  
Author(s):  
Q. Y. Hu ◽  
J.-F. Shu ◽  
W. G. Yang ◽  
C. Park ◽  
M. W. Chen ◽  
...  
Keyword(s):  
High Pressure ◽  
Transformation Pathways ◽  
Stability Limits

Molecular dynamics study of solid nitrogen at high pressure

1981 ◽  
Vol 59 (4) ◽  
pp. 530-534 ◽  
Author(s):  
Michael L. Klein ◽  
D. Levesque ◽  
J.-J. Weis
Keyword(s):  
Molecular Dynamics ◽  
High Pressure ◽  
Room Temperature ◽  
Power Spectra ◽  
Dynamical Behaviour ◽  
Dynamical Structure ◽  
Structure And Dynamics ◽  
Solid Nitrogen ◽  
Rotational Motions ◽  
Real Solid

A molecular dynamics study has been carried out of the structure and dynamics of solid nitrogen in its high pressure, room temperature, plastic crystal phase: cubic Pm3n. We employed a system of 512 molecules interacting via atom–atom potentials. As in the real solid our simulated crystal is composed of two types of molecules whose dynamical behaviour is quite distinct. We present calculations of the power spectra associated with translational and rotational motions as well as the phonon response embodied in the dynamical structure factor S(Q, ω).

scholarly journals Evidence for a high-pressure isostructural transition in nitrogen

2021 ◽  
Author(s):  
Chunmei Fan ◽  
Shan Liu ◽  
Jingyi Liu ◽  
Qiqi Tang ◽  
Binbin Wu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
High Pressure ◽  
Lattice Parameter ◽  
Molecular Symmetry ◽  
Solid Nitrogen ◽  
Slight Rotation ◽  
Pressure Phase ◽  
Important Objective ◽  
Isostructural Phase Transition

Abstract Understanding the high-pressure behaviors of diatomic molecules (H2, O2, N2, etc) is one of the most basic as well as important objective in high-pressure physics. Under high pressure diatomic molecule solids often exhibit rich crystal polymorphs. High-pressure isostructural transitions (HPIT) in solid hydrogen and oxygen, involving considerable technical challenges, have been experimentally documented, suggesting a possible prevailing pressure-driven molecular-symmetry breaking pathway. In spite of extensive efforts, however, HPIT in nitrogen has not been observed so far. Here we present a monoclinic-to-monoclinic isostructural phase transition (λ→λ’) in solid nitrogen at approximately 50 GPa accompanied with anomalies in lattice parameter, atomic volume and Raman vibron modes. Further ab initio calculations strongly confirmed the HPIT in nitrogen, showing the weak distortion of orientation and slight rotation in nitrogen molecules possibly drive the low-pressure phase, λ-N2, to an isostructural high-pressure phase, λ’-N2 without changing crystal symmetry. In addition, we probed in detail the phase stability and revisited the pressure-temperature (P-T) phase diagram of nitrogen, discovering a new high-pressure amorphous phase, η’-N2.

scholarly journals Multiple pathways in pressure-induced phase transition of coesite

2017 ◽  
Vol 114 (49) ◽  
pp. 12894-12899 ◽  
Author(s):  
Wei Liu ◽  
Xuebang Wu ◽  
Yunfeng Liang ◽  
Changsong Liu ◽  
Caetano R. Miranda ◽  
...  
Keyword(s):  
High Pressure ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Oxygen Sublattice ◽  
Dynamic Simulations ◽  
Precise Control ◽  
Amorphous Phases ◽  
Transformation Pathways ◽  
The One ◽  
Silica Phases

High-pressure single-crystal X-ray diffraction method with precise control of hydrostatic conditions, typically with helium or neon as the pressure-transmitting medium, has significantly changed our view on what happens with low-density silica phases under pressure. Coesite is a prototype material for pressure-induced amorphization. However, it was found to transform into a high-pressure octahedral (HPO) phase, or coesite-II and coesite-III. Given that the pressure is believed to be hydrostatic in two recent experiments, the different transformation pathways are striking. Based on molecular dynamic simulations with an ab initio parameterized potential, we reproduced all of the above experiments in three transformation pathways, including the one leading to an HPO phase. This octahedral phase has an oxygen hcp sublattice featuring 2 × 2 zigzag octahedral edge-sharing chains, however with some broken points (i.e., point defects). It transforms into α-PbO2 phase when it is relaxed under further compression. We show that the HPO phase forms through a continuous rearrangement of the oxygen sublattice toward hcp arrangement. The high-pressure amorphous phases can be described by an fcc and hcp sublattice mixture.

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