Assessment of dynamical and nondynamical correlation energy components for the beryllium-atom isoelectronic sequence

1999 ◽  
Vol 110 (5) ◽  
pp. 2343-2353 ◽  
Author(s):  
E. Valderrama ◽  
E. V. Ludeña ◽  
J. Hinze
Keyword(s):  
Correlation Energy ◽  
Isoelectronic Sequence ◽  
Energy Components

The Radius of the Coulomb Hole

1975 ◽  
Vol 53 (6) ◽  
pp. 592-597 ◽  
Author(s):  
Russell J. Boyd
Keyword(s):  
Correlation Energy ◽  
Radial Distance ◽  
General Tendency ◽  
Isoelectronic Sequence ◽  
Expectation Values ◽  
General Terms ◽  
Coulomb Hole ◽  
Radial Density Distribution ◽  
The Relationship ◽  
S States

The radius of the Coulomb hole in an atom or molecule is discussed in general terms and illustrated in detail for the ground state of the helium isoelectronic sequence. The calculations demonstrate a general tendency for the radius of the Coulomb hole to increase as a function of the distance of the reference electron from the nucleus and the existence of a nonzero lower limit (0.800 a.u. in He and 0.111 a.u. in Mg10+) for the radius of the Coulomb hole. This limit is slightly larger than the radial distance at which the radial density distribution reaches its maximum. By expressing the correlation energy of an atom in terms of certain one and two electron expectation values, the relationship between the correlation energy and the size and shape of the Coulomb hole is discussed. Detailed comparisons for the ground and 23S states of He are used to demonstrate the relationship.

Recent Radiative and Collisional Atomic Data of Astrophysical Interest

1988 ◽  
Vol 102 ◽  
pp. 129-132
Author(s):  
K.L. Baluja ◽  
K. Butler ◽  
J. Le Bourlot ◽  
C.J. Zeippen
Keyword(s):  
Mass Production ◽  
Bound States ◽  
Physical Models ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Atomic Data ◽  
Isoelectronic Sequence ◽  
Astrophysical Interest ◽  
Radiative Transitions ◽  
Forbidden Transitions

SummaryUsing sophisticated computer programs and elaborate physical models, accurate radiative and collisional atomic data of astrophysical interest have been or are being calculated. The cases treated include radiative transitions between bound states in the 2p4and 2s2p5configurations of many ions in the oxygen isoelectronic sequence, the photoionisation of the ground state of neutral iron, the electron impact excitation of the fine-structure forbidden transitions within the 3p3ground configuration of CℓIII, Ar IV and K V, and the mass-production of radiative data for ions in the oxygen and fluorine isoelectronic sequences, as part of the international Opacity Project.

Comparison of Conventional and Electron Spectroscopic Imaging in the Fixed Beam Electron Microscope of Ordered Protein Arrays

1985 ◽  
Vol 43 ◽  
pp. 74-75
Author(s):  
E. L. Buhle ◽  
U. Aebi
Keyword(s):  
Image Processing ◽  
Electron Microscope ◽  
High Resolution ◽  
Image Plane ◽  
Electron Spectroscopic Imaging ◽  
Protein Arrays ◽  
Beam Electron ◽  
Average Unit ◽  
Fixed Beam ◽  
Energy Components

CTEM brightfield images are formed by a combination of relatively high resolution elastically scattered electrons and unscattered and inelastically scattered electrons. In the case of electron spectroscopic images (ESI), the inelastically scattered electrons cause a loss of both contrast and spatial resolution in the image. In the case of ESI imaging on the Zeiss EM902, the transmited electrons are dispersed into their various energy components by passing them through a magnetic prism spectrometer; a slit is then placed in the image plane of the prism to select the electrons of a given energy loss for image formation. The purpose of this study was to compare CTEM with ESI images recorded on a Zeiss EM902 of ordered protein arrays. Digital image processing was employed to analyze the average unit cell morphologies of the two types of images.

Inelastic scattering at surfaces and interfaces

1986 ◽  
Vol 44 ◽  
pp. 392-393
Author(s):  
R. H. Ritchie ◽  
A. Howie
Keyword(s):  
Inelastic Scattering ◽  
Surface Properties ◽  
Correlation Energy ◽  
Condensed Matter ◽  
Charged Particles ◽  
Condensed Matter Physics ◽  
Optical Phonons ◽  
Exchange Correlation ◽  
Surfaces And Interfaces ◽  
Inelastic Interactions

An important part of condensed matter physics in recent years has involved detailed study of inelastic interactions between swift electrons and condensed matter surfaces. Here we will review some aspects of such interactions.Surface excitations have long been recognized as dominant in determining the exchange-correlation energy of charged particles outside the surface. Properties of surface and bulk polaritons, plasmons and optical phonons in plane-bounded and spherical systems will be discussed from the viewpoint of semiclassical and quantal dielectric theory. Plasmons at interfaces between dissimilar dielectrics and in superlattice configurations will also be considered.

A Combination of the Work Formalism for Exchange with an Optimized Correlation Energy Functional for Atoms

1995 ◽  
Vol 5 (9) ◽  
pp. 1277-1287 ◽  
Author(s):  
N. A. Cordero ◽  
K. D. Sen ◽  
J. A. Alonso ◽  
L. C. Balbás
Keyword(s):  
Correlation Energy ◽  
Energy Functional
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