Outstanding performance of configuration interaction singles and doubles using exact exchange Kohn-Sham orbitals in real-space numerical grid method

2016 ◽  
Vol 145 (22) ◽  
pp. 224309 ◽  
Author(s):  
Jaechang Lim ◽  
Sunghwan Choi ◽  
Jaewook Kim ◽  
Woo Youn Kim
Keyword(s):  
Configuration Interaction ◽  
Grid Method ◽  
Real Space ◽  
Numerical Grid ◽  
Exact Exchange

scholarly journals Configuration interaction singles based on the real-space numerical grid method: Kohn–Sham versus Hartree–Fock orbitals

2015 ◽  
Vol 17 (47) ◽  
pp. 31434-31443 ◽  
Author(s):  
Jaewook Kim ◽  
Kwangwoo Hong ◽  
Sunghwan Choi ◽  
Sang-Yeon Hwang ◽  
Woo Youn Kim
Keyword(s):  
Configuration Interaction ◽  
Grid Method ◽  
Real Space ◽  
Program Code ◽  
The Real ◽  
Hartree Fock ◽  
Numerical Grid

We developed a program code of CIS based on a numerical grid method and showed that Kohn–Sham orbitals from the Krieger–Li–Iafrate (KLI) approximation provide better reference configurations for CIS than the standard Hartree–Fock and Kohn–Sham orbitals.

Kohn–Sham approach for fast hybrid density functional calculations in real-space numerical grid methods

2018 ◽  
Vol 230 ◽  
pp. 21-26 ◽  
Author(s):  
Jaewook Kim ◽  
Sungwoo Kang ◽  
Jaechang Lim ◽  
Sang-Yeon Hwang ◽  
Woo Youn Kim
Keyword(s):  
Density Functional Calculations ◽  
Density Functional ◽  
Real Space ◽  
Numerical Grid ◽  
Hybrid Density Functional

scholarly journals Real-space numerical grid methods in quantum chemistry

2015 ◽  
Vol 17 (47) ◽  
pp. 31357-31359 ◽  
Author(s):  
Luca Frediani ◽  
Dage Sundholm
Keyword(s):  
Quantum Chemistry ◽  
Recent Progress ◽  
Real Space ◽  
Numerical Grid ◽  
Issue Reports

This themed issue reports on recent progress in the fast developing field of real-space numerical grid methods in quantum chemistry.

An auxilliary grid method for the calculation of electrostatic terms in density functional theory on a real-space grid

2015 ◽  
Vol 17 (47) ◽  
pp. 31550-31557 ◽  
Author(s):  
Michael Zuzovski ◽  
Amir Boag ◽  
Amir Natan
Keyword(s):  
Density Functional Theory ◽  
Domain Decomposition ◽  
Density Functional ◽  
Grid Method ◽  
Real Space ◽  
Functional Theory ◽  
Space Grid ◽  
Uniform Grids

The calculation of electrostatic integrals is performed using domain decomposition and auxiliary non-uniform grids for density functional theory real-space implementation.

High-resolution structure determination by ALCHEMI

1983 ◽  
Vol 41 ◽  
pp. 178-181 ◽  
Author(s):  
Peter G. Self ◽  
Peter R. Buseck
Keyword(s):  
Site Occupancy ◽  
Real Space ◽  
Unit Cell ◽  
Bragg Angle ◽  
Electron Current ◽  
High Resolution Structure ◽  
Beam Incident ◽  
Crystallographic Planes ◽  
Electron Beam Incident ◽  
Resolution Structure

ALCHEMI (Atom Location by CHanneling Enhanced Microanalysis) enables the site occupancy of atoms in single crystals to be determined. In this article the fundamentals of the method for both EDS and EELS will be discussed. Unlike HRTEM, ALCHEMI does not place stringent resolution requirements on the microscope and, because EDS clearly distinguishes between elements of similar atomic number, it can offer some advantages over HRTEM. It does however, place certain constraints on the crystal. These constraints are: a) the sites of interest must lie on alternate crystallographic planes, b) the projected charge density on the alternate planes must be significantly different, and c) there must be at least one atomic species that lies solely on one of the planes.An electron beam incident on a crystal undergoes elastic scattering; in reciprocal space this is seen as a diffraction pattern and in real space this is a modulation of the electron current across the unit cell. When diffraction is strong (i.e., when the crystal is oriented near to the Bragg angle of a low-order reflection) the electron current at one point in the unit cell will differ significantly from that at another point.

An Image Reconstruction System Applied to High Voltage Microscopy

1975 ◽  
Vol 33 ◽  
pp. 292-293
Author(s):  
D. E. Johnson
Keyword(s):  
High Voltage ◽  
Prior Information ◽  
Block Diagram ◽  
Three Dimensional ◽  
Real Space ◽  
Two Dimensional ◽  
Efficient Manner ◽  
Fourier Methods ◽  
Tilt Series ◽  
Methods Of Reconstruction

Increased specimen penetration; the principle advantage of high voltage microscopy, is accompanied by an increased need to utilize information on three dimensional specimen structure available in the form of two dimensional projections (i.e. micrographs). We are engaged in a program to develop methods which allow the maximum use of information contained in a through tilt series of micrographs to determine three dimensional speciman structure.In general, we are dealing with structures lacking in symmetry and with projections available from only a limited span of angles (±60°). For these reasons, we must make maximum use of any prior information available about the specimen. To do this in the most efficient manner, we have concentrated on iterative, real space methods rather than Fourier methods of reconstruction. The particular iterative algorithm we have developed is given in detail in ref. 3. A block diagram of the complete reconstruction system is shown in fig. 1.

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