scholarly journals Heterodyne Interferometer for Measurement of Electron Density in High-Pressure Plasmas

10.5772/38576 ◽  
2012 ◽  
Author(s):  
Keiichiro Urabe ◽  
Kunihide Tachib
Keyword(s):  
High Pressure ◽  
Electron Density ◽  
Heterodyne Interferometer

The application of evolution strategies to disordered structures

1999 ◽  
Vol 32 (5) ◽  
pp. 902-910 ◽  
Author(s):  
Karsten Knorr ◽  
Fritz Mädler
Keyword(s):  
High Pressure ◽  
Maximum Entropy ◽  
Electron Density ◽  
Structural Model ◽  
Evolution Strategies ◽  
Qualitative Model ◽  
Density Distributions ◽  
Disordered Structures ◽  
Structure Factors ◽  
Complex Anions

Evolution strategies are applied to refine structural fragments, like molecules or complex anions, of orientationally disordered crystals. Optimal geometric embedding of the fragments into electron density distributions, resulting from maximum-entropy (ME) reconstructions, are performed. The evolution paradigm is found to be also applicable for the refinement against structure factors, for which the structural model is carefully selected from the ME densities. Suitably modified, the method is used successfully to compute reorientation pathways and to predict disordered high-pressure configurations in a non-classical qualitative model.

scholarly journals Exploring charge density analysis in crystals at high pressure: data collection, data analysis and advanced modelling

2017 ◽  
Vol 73 (4) ◽  
pp. 584-597 ◽  
Author(s):  
Nicola Casati ◽  
Alessandro Genoni ◽  
Benjamin Meyer ◽  
Anna Krawczuk ◽  
Piero Macchi
Keyword(s):  
High Pressure ◽  
Density Distribution ◽  
Charge Density ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Theoretical Work ◽  
Specific Information ◽  
Collection Data ◽  
Modelling Techniques ◽  
Density Analysis

The possibility to determine electron-density distribution in crystals has been an enormous breakthrough, stimulated by a favourable combination of equipment for X-ray and neutron diffraction at low temperature, by the development of simplified, though accurate, electron-density models refined from the experimental data and by the progress in charge density analysis often in combination with theoretical work. Many years after the first successful charge density determination and analysis, scientists face new challenges, for example: (i) determination of the finer details of the electron-density distribution in the atomic cores, (ii) simultaneous refinement of electron charge and spin density or (iii) measuring crystals under perturbation. In this context, the possibility of obtaining experimental charge density at high pressure has recently been demonstrated [Casatiet al.(2016).Nat. Commun.7, 10901]. This paper reports on the necessities and pitfalls of this new challenge, focusing on the speciessyn-1,6:8,13-biscarbonyl[14]annulene. The experimental requirements, the expected data quality and data corrections are discussed in detail, including warnings about possible shortcomings. At the same time, new modelling techniques are proposed, which could enable specific information to be extracted, from the limited and less accurate observations, like the degree of localization of double bonds, which is fundamental to the scientific case under examination.

Imaging of Electron Density Distribution of CeP Under High Pressure by Single Crystal SR X-Ray Experiments

2001 ◽  
Vol 70 (4) ◽  
pp. 1162-1163 ◽  
Author(s):  
Takahisa Shobu ◽  
Yukio Noda ◽  
Kazuaki Iwasa ◽  
Abdul Hannan ◽  
Masahumi Kohgi ◽  
...  
Keyword(s):  
High Pressure ◽  
Density Distribution ◽  
Single Crystal ◽  
Electron Density ◽  
Electron Density Distribution ◽  
X Ray

1112 Electron Density Measurements of Shock Wave Plasmas by CO_2 Laser Heterodyne Interferometer

2005 ◽  
Vol 2005.80 (0) ◽  
pp. _11-23_-_11-24_
Author(s):  
Yoshikazu ASAMI ◽  
Takeyoshi FUJITA ◽  
Sumio NAHARA ◽  
Shigeyoshi HISADA
Keyword(s):  
Shock Wave ◽  
Electron Density ◽  
Density Measurements ◽  
Heterodyne Interferometer ◽  
Laser Heterodyne

Measurements of electron density of shocked plasma by CO_2 laser heterodyne interferometer

2002 ◽  
Vol 2002.77 (0) ◽  
pp. _10-21_-_10-22_
Author(s):  
Naokazu TAKAZAWA ◽  
Takeyoshi FUJITA ◽  
Sumio NAKAHARA ◽  
Shigeyoshi HISADA
Keyword(s):  
Electron Density ◽  
Heterodyne Interferometer ◽  
Laser Heterodyne

scholarly journals Temporal measurements of the electron density in high-pressure electron- beam excited xenon plasmas

1975 ◽  
Author(s):  
E. Zamir ◽  
C.W. Werner ◽  
W.P. Lapatovich ◽  
E.V. George
Keyword(s):  
High Pressure ◽  
Electron Beam ◽  
Electron Density
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