The structure of fluid argon from high-pressure neutron diffraction andab initiomolecular dynamics simulations

1999 ◽  
Vol 111 (6) ◽  
pp. 2641-2646 ◽  
Author(s):  
Till Pfleiderer ◽  
Isabella Waldner ◽  
Helmut Bertagnolli ◽  
Klaus Tödheide ◽  
Barbara Kirchner ◽  
...  
Keyword(s):  
High Pressure ◽  
Neutron Diffraction ◽  
Fluid Argon ◽  
Dynamics Simulations

Igor Goncharenko: a pioneer in high-pressure neutron diffraction

2008 ◽  
Vol 28 (2) ◽  
pp. 141-142 ◽  
Author(s):  
I. Mirebeau ◽  
J.-M. Mignot
Keyword(s):  
High Pressure ◽  
Neutron Diffraction

scholarly journals High-Pressure Transformation ofSiO2Glass from a Tetrahedral to an Octahedral Network: A Joint Approach Using Neutron Diffraction and Molecular Dynamics

2014 ◽  
Vol 113 (13) ◽  
Author(s):  
Anita Zeidler ◽  
Kamil Wezka ◽  
Ruth F. Rowlands ◽  
Dean A. J. Whittaker ◽  
Philip S. Salmon ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
High Pressure ◽  
Neutron Diffraction ◽  
Joint Approach

Neutron-diffraction study of γ-Fe at high pressure

1994 ◽  
Vol 50 (6) ◽  
pp. 3532-3535 ◽  
Author(s):  
Akifumi Onodera ◽  
Yorihiko Tsunoda ◽  
Nobuhiko Kunitomi ◽  
O. Allan Pringle ◽  
Robert M. Nicklow ◽  
...  
Keyword(s):  
High Pressure ◽  
Neutron Diffraction ◽  
Diffraction Study ◽  
Neutron Diffraction Study

scholarly journals Phase Transition and Polymerization of Acetonitrile under High Pressure

2014 ◽  
Vol 70 (a1) ◽  
pp. C763-C763
Author(s):  
Haiyan Zheng ◽  
Kuo Li ◽  
George Cody ◽  
Chris Tulk ◽  
Jamie Molaison ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Reaction Mechanism ◽  
Neutron Diffraction ◽  
Raman Spectra ◽  
Hydrogen Transfer ◽  
Layer Structure ◽  
Van Der Waals ◽  
Orthorhombic Phase ◽  
Organic Polymer

Successful application of high pressure on synthesis of organic polymer, including the conducting polymer and super hard materials depends on the knowledge of reaction mechanism. The evolution of crystal structure under high pressure especially the structure close to transition pressure is crucial to conclude the reaction mechanism. Nitriles represent a large class of interstellar molecules and are the potential source of amino acids. Understanding its behavior at extreme conditions has gained increasing attention recently. Acetonitrile (CH3CN), the simplest organic compound with C≡N triple bond, can act as a model system for studying the pressure induced polymerization. The phase transition of acetonitrile under high pressure has been studied extensively.[1-3] However, it is still controversial and there is no any detailed discussion about its polymerization mechanism under high pressure. Here, we report the in-situ high pressure Raman spectra and powder neutron diffraction results on CD3CN, which indicates a minor phase transition at 5 GPa. The neutron diffraction shows that CD3CN keeps the orthorhombic phase from 1.66 GPa to 20.58 GPa which is very close to the reaction pressure. The week hydrogen bonding CD...N arranges the molecule into 3-dimensional framework which can be treated as two sets of diamond like structures interpenetrating with each other. Interestingly, the observed N...D distance is 1.984 Å at 20.58 GPa, shorter than the van der Waals distance of N...H (2.75 Å) by 28%. The van der Waals separation is often taken as a reference distance for the molecular instability. Thus, a hydrogen transfer process during the polymerization can be concluded. This deduction is also supported by the solid state NMR and FTIR results of the recovered polymerized CH3CN (p-CH3CN) from high pressure. In addition, the atomic pair distribution function and Raman spectra indicate the p-CD3CN or p-CH3CN has a random packed layer structure with nano-graphene lattice.

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