Choice of the optimal basis set in calculations on many atom inorganic molecules using the non-empirical MO LCAO SSP method

1970 ◽  
Vol 10 (5) ◽  
pp. 772-777 ◽  
Author(s):  
N. M. Klimenko ◽  
M. E. Dyatkina
Keyword(s):  
Basis Set ◽  
Optimal Basis ◽  
Inorganic Molecules

The choice of the optimal basis set for the 4th period atoms from Cu to Kr in SCF LCAO MO calculations on complex inorganic molecules

1973 ◽  
Vol 13 (4) ◽  
pp. 705-707
Author(s):  
S. P. Dolin ◽  
B. F. Shchegolev ◽  
N. M. Klimenko ◽  
E. L. Rozenberg ◽  
M. E. Dyatkina
Keyword(s):  
Basis Set ◽  
Mo Calculations ◽  
Optimal Basis ◽  
Inorganic Molecules ◽  
Lcao Mo

AB-INITIO CALCULATIONS OF ELECTRONIC PROPERTIES OF InP AND GaP

2013 ◽  
Vol 27 (15) ◽  
pp. 1362013
Author(s):  
Y. MALOZOVSKY ◽  
L. FRANKLIN ◽  
E. C. EKUMA ◽  
G. L. ZHAO ◽  
D. BAGAYOKO
Keyword(s):  
Ab Initio ◽  
Electronic Properties ◽  
Gallium Phosphide ◽  
Local Density ◽  
Basis Set ◽  
High Symmetry ◽  
Optimal Basis ◽  
Direct Band ◽  
Experimental Values ◽  
Experimental Findings

We present results from ab-initio, self-consistent local density approximation (LDA) calculations of electronic and related properties of zinc blende indium phosphide (InP) and gallium phosphide (GaP) . We employed a LDA potential and implemented the linear combination of atomic orbitals (LCAO) formalism. This implementation followed the Bagayoko, Zhao and Williams (BZW) method, as enhanced by Ekuma and Franklin (BZW–EF). This method searches for the optimal basis set that yields the minima of the occupied energies. This search entails increases of the size of the basis set and the related modifications of angular symmetry and of radial orbitals. Our calculated, direct band gap of 1.398 eV (1.40 eV), at the Γ point, is in excellent agreement with experimental values, for InP , and our preliminary result for the indirect gap of GaP is 2.135 eV, from the Γ to X high symmetry points. We have also calculated electron and hole effective masses for both InP and GaP . These calculated properties also agree with experimental findings. We conclude that the BZW–EF method could be employed in calculations of electronic properties of high-Tc superconducting materials to explain their complex properties.

scholarly journals Photoemission Spectra from the Extended Koopman’s Theorem, Revisited

2021 ◽  
Vol 9 ◽  
Author(s):  
S. Di Sabatino ◽  
J. Koskelo ◽  
J. Prodhon ◽  
J. A. Berger ◽  
M. Caffarel ◽  
...  
Keyword(s):  
Spectral Function ◽  
Secular Equation ◽  
Basis Set ◽  
Effective Energy ◽  
Bulk Silicon ◽  
Many Body ◽  
Optimal Basis ◽  
Diagonal Approximation ◽  
Energy Theory ◽  
The Many

The Extended Koopman’s Theorem (EKT) provides a straightforward way to compute charged excitations from any level of theory. In this work we make the link with the many-body effective energy theory (MEET) that we derived to calculate the spectral function, which is directly related to photoemission spectra. In particular, we show that at its lowest level of approximation the MEET removal and addition energies correspond to the so-called diagonal approximation of the EKT. Thanks to this link, the EKT and the MEET can benefit from mutual insight. In particular, one can readily extend the EKT to calculate the full spectral function, and choose a more optimal basis set for the MEET by solving the EKT secular equation. We illustrate these findings with the examples of the Hubbard dimer and bulk silicon.

Ab-initio Calculations of Electronic, Transport, and Bulk Properties of cubic Boron Nitride (zb-BN)

2015 ◽  
Vol 9 (1) ◽  
pp. 2277-2286 ◽  
Author(s):  
Anthony Duane Stewart
Keyword(s):  
Boron Nitride ◽  
Ab Initio ◽  
Excellent Agreement ◽  
Local Density ◽  
Cubic Boron Nitride ◽  
Basis Set ◽  
Optimal Basis ◽  
Valence Bands ◽  
Indirect Band Gap ◽  
Experimental Values

We present results from ab-initio, self consistent, local density approximation (LDA) calculations of electronic and related properties of cubic boron nitride (zb-BN).  We employed the Ceperley and Alder LDA potential and the linear combination of atomic orbitals (LCAO) formalism in our non-relativistic computations.  We solved the system of LDA equations self-consistently, through the implementation of the LCAO formalism, following the Bagayoko, Zhao, and Williams (BZW) method as enhanced by Ekuma and Franklin (BZW-EF).  The BZW-EF method includes a methodical search for the optimal basis set that yields the absolute minima of the occupied energies.  This search entails increasing the size of the basis set and the related modifications of angular symmetry and of radial orbitals.  Our calculated, indirect band gap of 6.48 eV, from the Γ to the Χ points, and bulk modulus of 375 GPa are in excellent agreement with corresponding experimental values at room temperature (RT).  The calculated widths of the lowest valance band and that of the entire valence bands of 5.65 eV and 20.26 eV are in excellent agreement with the measured values of 5.5 eV and 20 eV, respectively.  We have also calculated electron and hole effective masses for zb-BN, and the total (DOS) and partial (pDOS) densities of states.   

Ab initio and MNDO Calculations of the 35Cl NQR Parameters of Some Organic and Inorganic Molecules

1996 ◽  
Vol 51 (5-6) ◽  
pp. 549-553 ◽  
Author(s):  
Valentin P. Feshin ◽  
Mikhail Yu. Konshin
Keyword(s):  
Ab Initio ◽  
Basis Set ◽  
Hartree Fock ◽  
Mndo Calculations ◽  
Inorganic Molecules ◽  
Asymmetry Parameters ◽  
Linear Correlations ◽  
Split Valence ◽  
Valence Basis Set ◽  
Good Agreement

Abstract The results of ab initio and MNDO calculations of the Cl2C = CHOCH3 , XCOCl (X = CH3 , OCH3 and COCl), 4-ClC6H4CH2Cl, (CNCl)3 and PCl5 with total optimization of their geometry are presented. The ab initio calculations were executed using Hartree-Fock theory and the split valence basis set 6-31G* (RHF/6-31 G*//RHF/6-31G*). Using the calculated p-orbital populations of the CI atoms in these molecules the 35Cl NQR frequencies and asymmetry parameters of the EFG at the 35Cl nuclei have been determined. When the populations of the less diffuse components of orbitals in the split valence basis set are used the calculated and experimenal ν and η values are in good agreement. Linear correlations between these calculated and corresponding experimental ν and η values are obtained. The causes of the nonconformity of the earlier calculated ν and η values and their experimental ones are analysed.

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