Frozen core approximation for atoms and atomic ions

1968 ◽  
Vol 46 (23) ◽  
pp. 2675-2678 ◽  
Author(s):  
R. P. McEachran ◽  
C. E. Tull ◽  
M. Cohen
Keyword(s):  
Valence Electron ◽  
Atomic Systems ◽  
Atomic Ions ◽  
Hartree Fock ◽  
Core Approximation

Properties of the frozen core approximation for atomic systems containing one valence electron in addition to completely filled shells are derived. It is shown that, in addition to computational convenience, the procedure enjoys certain theoretical advantages over the standard Hartree–Fock approximation.

Physical properties of many-electron atomic systems evaluated from analytical Hartree-Fock functions

1968 ◽  
Vol 10 (5) ◽  
pp. 388-392 ◽  
Author(s):  
Jon Thorhallsson ◽  
Carolyn Fisk ◽  
Serafin Fraga
Keyword(s):  
Physical Properties ◽  
Atomic Systems ◽  
Hartree Fock

Orbit–orbit interaction inn fN electron configurations

1969 ◽  
Vol 47 (17) ◽  
pp. 1885-1888 ◽  
Author(s):  
K. M. S. Saxena ◽  
G. Malli
Keyword(s):  
Orbit Interaction ◽  
Matrix Elements ◽  
Atomic Systems ◽  
Hartree Fock ◽  
The Matrix

The expressions of the matrix elements of the orbit–orbit interaction for various fN electron configurations are computed and tabulated for general usage. These expressions are used to evaluate the Hartree–Fock values of the orbit–orbit interaction in all the states for a large number of fN electron atomic systems.

Bonding in H3AB compounds

1985 ◽  
Vol 63 (7) ◽  
pp. 1609-1615 ◽  
Author(s):  
Michael W. Schmidt ◽  
Mark S. Gordon
Keyword(s):  
Phosphine Oxide ◽  
Valence Electron ◽  
Amine Oxide ◽  
Localized Orbitals ◽  
Ionic Complexes ◽  
Hartree Fock ◽  
Synthetic Target ◽  
Phosphine Sulfide

The nature of binding in the 14 valence electron H3AB molecules is examined, where A and B are taken from the second and third rows. The AB bonding is inferred from the computed structures, d orbital populations, and localized orbitals. Near Hartree–Fock results are reported for the strongest bonding compounds, which are those with third row atoms A, and second row atoms B. Phosphine oxide, and to a lesser extent phosphine sulfide, are found to be effectively doubly bound. Amine oxide and sulfide are found to be ionic complexes. The thiazyl bond is confirmed as triple in nature. The exotic compound F3IC is proposed as a synthetic target.

Compton Profiles and Nature of Bonding in Tantalum Chalcogenides

2013 ◽  
Vol 209 ◽  
pp. 143-146
Author(s):  
K.C. Bhamu ◽  
Arvind Sharma ◽  
Asvin R. Jani ◽  
B.L. Ahuja
Keyword(s):  
Linear Combination ◽  
Density Functional ◽  
Valence Electron ◽  
Population Analysis ◽  
Theoretical Data ◽  
Hartree Fock ◽  
Line Shapes ◽  
Valence Electron Density ◽  
Γ Ray ◽  
Gaussian Orbitals

Abstract. We report the Compton profiles of tantalum chalcogenides (TaS2 and TaSSe) using Hartree–Fock and hybridization of Hartree–Fock and density functional theories within linear combination of atomic (Gaussian) orbitals. To interpret the theoretical data on Compton line shapes, we have measured the Compton profiles using our in-house 100 mCi 241Am γ-ray Compton spectrometer. To understand the relative nature of bonding, we have obtained the equal-valence-electron-density (EVED) profiles. The EVED profiles shows that charge in TaSSe is more localized than TaS2 in the bonding direction which confirms that TaSSe is more covalent than TaS2, which is in agreement with the Mulliken’s population analysis.

Physical properties of many-electron atomic systems evaluated from analytical Hartree-Fock functions

1968 ◽  
Vol 12 (1) ◽  
pp. 80-84 ◽  
Author(s):  
Jon Thorhallsson ◽  
Carolyn Fisk ◽  
Serafin Fraga
Keyword(s):  
Physical Properties ◽  
Atomic Systems ◽  
Hartree Fock

CALCULATION OF THEORETICAL ISOTROPIC COMPTON PROFILE FOR MANY PARTICLE SYSTEMS

2010 ◽  
Vol 24 (14) ◽  
pp. 1601-1614
Author(s):  
ALI A. ALZUBADI ◽  
KHALIL H. ALBAYATI
Keyword(s):  
Wave Function ◽  
Impulse Approximation ◽  
Particle Systems ◽  
Electron Interaction ◽  
Compton Profile ◽  
High Momentum ◽  
Atomic Systems ◽  
Hartree Fock ◽  
Hf Wave ◽  
Momentum Region

Theoretical isotropic (spherically symmetric) Compton profiles (ICP) have been calculated for many particle systems' He , Li , Be and B atoms in their ground states. Our calculations were performed using Roothan–Hartree–Fock (RHF) wave function, HF wave function of Thakkar and re-optimized HF wave function of Clementi–Roetti, taking into account the impulse approximation. The theoretical analysis included a decomposition of the various intra and inter shells and their contributions in the total ICP. A high momentum region of up to 4 a.u. was investigated and a non-negligible tail was observed in all ICP curves. The existence of a high momentum tail was mainly due to the electron–electron interaction. The ICP for the He atom has been compared with the available experimental data and it is found that the ICP values agree very well with them. A few low order radial momentum expectation values 〈pn〉 and the total energy for these atomic systems have also been calculated and compared with their counterparts' wave functions.

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