scholarly journals Application of the dielectric-dependent screened exchange potential approach to organic photocell materials

2016 ◽  
Vol 18 (39) ◽  
pp. 27554-27563 ◽  
Author(s):  
Tomomi Shimazaki ◽  
Takahito Nakajima
Keyword(s):  
Organic Molecules ◽  
Exchange Potential ◽  
Potential Approach ◽  
Screened Exchange

This paper discusses the fundamental features of the dielectric-dependent screened exchange potential approach for organic molecules and photocell materials.

A calculation of the phonon frequencies in sodium

1965 ◽  
Vol 283 (1392) ◽  
pp. 33-49 ◽  
Keyword(s):  
Phonon Scattering ◽  
Effective Interaction ◽  
Harmonic Approximation ◽  
Potential Method ◽  
Exchange Potential ◽  
Hartree Fock ◽  
Screened Exchange ◽  
Effective Attraction ◽  
Comparison Of The Results ◽  
Pseudo Potential

The phonon spectrum of sodium is calculated in the harmonic approximation. The effective interaction between the ions is separated into direct two-body forces between bare ions and effective attraction due to the presence of conduction electrons. Careful treatment of the two-phonon processes includes the calculation of the electron-phonon scattering based on the pseudo-potential method and the screening effects due to the interaction between electrons by the Hartree-Fock approximation with a screened exchange potential. Comparison of the results for sodium with neutron diffraction measurements and a previous calculation by Toya shows good agreement on the whole. It is hoped that this method may be applied to some other metals.

Theoretical Investigation of Cubic BaVO3 and LaVO3 Perovskites via Tran–Blaha-Modified Becke–Johnson Exchange Potential Approach

2017 ◽  
Vol 30 (11) ◽  
pp. 3129-3136 ◽  
Author(s):  
Muhammad Rashid ◽  
Zafar Abbas ◽  
M. Yaseen ◽  
Qadeer Afzal ◽  
Asif Mahmood ◽  
...  
Keyword(s):  
Theoretical Investigation ◽  
Exchange Potential ◽  
Potential Approach

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

Direct phase determination in electron crystallography: small organic molecules

1992 ◽  
Vol 50 (2) ◽  
pp. 1166-1167
Author(s):  
Douglas L. Dorset
Keyword(s):  
Organic Molecules ◽  
Data Sets ◽  
Temperature Structure ◽  
3D Analysis ◽  
Intensity Data ◽  
Electron Crystallography ◽  
Phase Determination ◽  
Measured Intensity ◽  
3D Data

The quantitative use of electron diffraction intensity data for the determination of crystal structures represents the pioneering achievement in the electron crystallography of organic molecules, an effort largely begun by B. K. Vainshtein and his co-workers. However, despite numerous representative structure analyses yielding results consistent with X-ray determination, this entire effort was viewed with considerable mistrust by many crystallographers. This was no doubt due to the rather high crystallographic R-factors reported for some structures and, more importantly, the failure to convince many skeptics that the measured intensity data were adequate for ab initio structure determinations.We have recently demonstrated the utility of these data sets for structure analyses by direct phase determination based on the probabilistic estimate of three- and four-phase structure invariant sums. Examples include the structure of diketopiperazine using Vainshtein's 3D data, a similar 3D analysis of the room temperature structure of thiourea, and a zonal determination of the urea structure, the latter also based on data collected by the Moscow group.

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