A simplified core pseudopotential model for use in valence-electron molecular SCF calculations

1978 ◽  
Vol 31 (12) ◽  
pp. 2571 ◽  
Author(s):  
E Nagy-Felsobuki ◽  
JB Peel
Keyword(s):  
Valence Electron ◽  
Ground States ◽  
Model Potential ◽  
Basis Sets ◽  
Bond Lengths ◽  
The Core ◽  
Orbital Energies ◽  
Scf Calculations

A molecular valence-electron-only model potential (VEOMP) method is proposed in which the core-valence interpenetration term is replaced by an exponential screening function and the core-valence orthogonality is represented by a pseudopotential term in which the required parametrization is minimized without compromising the effectiveness of the method. This model has been incorporated in the GAUSSIAN 70 programs, and sample calculations, using the STO-3G and STO-6G minimum basis sets, are reported for the orbital energies and equilibrium bond lengths of the ground states of N2, PN and P2.

Structural properties of Na atom under impenetrable spatialconfinement

2021 ◽  
Author(s):  
Santanu Mondal ◽  
K.D. Sen ◽  
Jayanta K. Saha
Keyword(s):  
Angular Momentum ◽  
Structural Properties ◽  
Excited States ◽  
Orbital Angular Momentum ◽  
Valence Electron ◽  
Model Potential ◽  
The Core ◽  
Quantum Numbers

The structural properties and radial distributions of valence electron in different excited levels of Na atom [n = 3 − 5, l = 0 − 4; n and l being the principal and orbital angular momentum quantum numbers, respectively] under impenetrable spherical confinement has been studied, where the interaction between the frozen core and the valence electron is mimicked by model potential available in the literature. The effect of the core on the valence electron has been investigated by estimating the structural properties of Na10+ ion under similar confinement. Scaled radial densities at the nucleus and related ratios are presented for few excited states of the valence electron of Na atom and the corresponding analytic results have been tested numerically.

scholarly journals Pseudopotential Calculations for Li2, Na2 and NaLi

1988 ◽  
Vol 41 (4) ◽  
pp. 563 ◽  
Author(s):  
N Andriopoulos ◽  
EI von Nagy-Felsobuki
Keyword(s):  
Potential Energy ◽  
Ab Initio ◽  
Electronic State ◽  
Valence Electron ◽  
Large Range ◽  
Model Potential ◽  
Potential Energy Curves ◽  
Basis Sets ◽  
Valence Orbital ◽  
Pseudopotential Calculations

A valence-electron only model potential (V ALMOP) pseudopotential method has been developed utilising the GAUSSIAN 76 integral packages. VALMOP and the reference ab initio potential energy curves have been calculated for the ground electronic state of Li2, Na2 and NaLi using a number of different basis sets. Comparisons indicate that V ALMOP accurately reproduces internuclear bondlengths, valence orbital eigenvalues and, moreover, the shape of the all-electron potential energy curves over a large range of bondlength R.

The effect of ionic lattices on the electronic structures of polyatomic ions. I. The triiodide ion

1966 ◽  
Vol 19 (9) ◽  
pp. 1567 ◽  
Author(s):  
RD Brown ◽  
EK Nunn
Keyword(s):  
Electronic Structure ◽  
Molecular Orbital ◽  
Electron Energy ◽  
Electronic Structures ◽  
Valence Electron ◽  
Bond Orders ◽  
Bond Lengths ◽  
Molecular Orbital Study ◽  
Crystalline Environment ◽  
Asymmetric Stretch

A VESCF molecular-orbital study of the electronic structure of the triiodide anion in its crystalline environment in caesium triiodide and in tetraphenylarsonium triiodide reveals the effect of the lattices upon the electronic structures. The calculated total valence-electron energy as a function of the position of the central iodine nucleus provides an understanding of the observed geometries of the anion in the two crystals. The energy plot also implies that the asymmetric stretch of the triiodide is strongly anharmonic in the crystal. A satisfactory correlation exists between observed iodine : iodine bond lengths and computed bond orders.

The Photoelectron Spectra the Chloro Toluenes

1987 ◽  
Vol 40 (4) ◽  
pp. 751 ◽  
Author(s):  
JB Peel ◽  
EI Vonnagyfelsobuki
Keyword(s):  
Ab Initio ◽  
Cross Section ◽  
Valence Electron ◽  
Model Potential ◽  
Ionization Potentials ◽  
Photoelectron Spectra ◽  
Molecule Model ◽  
Linear Correlations ◽  
Spectral Assignment

The HeI and HeII photoelectron spectra of the chloro toluenes have been measured. The spectra are assigned using HeI/HeII cross-section ratios and a composite-molecule model within an ab initio valence-electron-only model potential (VEOMP) framework. The order of the first two ionization potentials for the chloro toluenes is assigned as πS < πA which is contrary to the VEOMP assignment for benzal chloride and benzotrichloride , but is consistent with linear correlations using group electronegativities and σI scales. Furthermore, linear correlations using the first two ionization potentials of fluoro and chloro toluenes with group electronegativities are shown to be a useful aid in spectral assignment and, moreover, suggest that for benzyl fluoride and benzal chloride the most appropriate σI values are 0.20 and 0.31 respectively.

1994 Polanyi Award Lecture Concept of active electrons in chemistry

1995 ◽  
Vol 73 (5) ◽  
pp. 619-628 ◽  
Author(s):  
Sigeru Huzinaga
Keyword(s):  
Solid State ◽  
Relativistic Effects ◽  
Potential Method ◽  
Model Potential ◽  
Computational Method ◽  
Computational Accuracy ◽  
The Core ◽  
Way Of Thinking

The notion of division between active and dormant electrons has been well received and widely used in the chemists' way of thinking. The core–valence separation in atoms is the best-known example. This paper describes a theoretical and computational method called the model potential method, which deals only with active electrons in molecular and solid state calculations. The method is capable of reaching computational accuracy of testing the validity of the separation of active and dormant electrons in individual cases. Keywords: separability of electrons, model potential method, valence orbitals, relativistic effects.

Effect of basis sets on ab initio SCF calculations of molecular hardness

1994 ◽  
Vol 306 (1) ◽  
pp. 87-90 ◽  
Author(s):  
S. Nath ◽  
A.B. Sannigrahi ◽  
P.K. Chattaraj
Keyword(s):  
Ab Initio ◽  
Basis Sets ◽  
Scf Calculations

Zur Besdireibung von Atonirümpfen init kleinen Basissätzen im Rahmen des SCF-MO-LCGO-Verfahrens / Describing of the core with small basis sets of the SCF-MO-LCGO-method

1973 ◽  
Vol 28 (6) ◽  
pp. 1036-1037
Author(s):  
S.-J. Wang
Keyword(s):  
Basis Sets ◽  
The Core ◽  
Total Energies ◽  
Stable Core ◽  
Molecular Calculations

The approximation of the stable core has been investigated, using small basis sets of the SCF -MO -LCGO-method. The results of the calculated three Gauss-functions and the total energies for the configuration (1s)2 (2s)2 of B+, C2+, N3+, O4+ and F5+ are given and compared with the basis sets of five Gauss-functions. A discussion on the quality of these basis sets for molecular calculations is given.

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