scholarly journals Mott gapping in 3dABO3 perovskites without Mott-Hubbard interelectronic repulsion energy U

2019 ◽  
Vol 100 (3) ◽  
Author(s):  
Julien Varignon ◽  
Manuel Bibes ◽  
Alex Zunger
Keyword(s):  
Repulsion Energy

Hardness and HOMO-LUMO Gap Probed by the Helium Atom Pushing the Molecular Surface of the First-Row Hydride Molecules

2003 ◽  
Vol 68 (12) ◽  
pp. 2344-2354 ◽  
Author(s):  
Edyta Małolepsza ◽  
Lucjan Piela
Keyword(s):  
Helium Atom ◽  
Pauli Exclusion Principle ◽  
Structure Change ◽  
Molecular Surface ◽  
Exclusion Principle ◽  
Probe Position ◽  
Repulsion Energy ◽  
Ionic Dissociation ◽  
Probe Site ◽  
Homo Lumo

A molecular surface defined as an isosurface of the valence repulsion energy may be hard or soft with respect to probe penetration. As a probe, the helium atom has been chosen. In addition, the Pauli exclusion principle makes the electronic structure change when the probe pushes the molecule (at a fixed positions of its nuclei). This results in a HOMO-LUMO gap dependence on the probe site on the isosurface. A smaller gap at a given probe position reflects a larger reactivity of the site with respect to the ionic dissociation.

scholarly journals Theoretical Study of Thermal Cracking For Acenaphthylene Molecule

2013 ◽  
Vol 10 (3) ◽  
pp. 1071-1081
Author(s):  
Baghdad Science Journal
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Reaction Path ◽  
Polyaromatic Hydrocarbons ◽  
Thermal Cracking ◽  
Triplet States ◽  
Bond Energies ◽  
Functional Theory ◽  
Repulsion Energy ◽  
Bond Breakage

Density Functional Theory (DFT) calculations were carried out to study the thermal cracking for acenaphthylene molecule to estimate the bond energies for breaking C8b-C5a , C5a-C5 , C5-C4 , and C5-H5 bonds as well as the activation energies. It was found that for C8b-C5a , C5-C4 , and C5-H5 reactions it is often possible to identify one pathway for bond breakage through the singlet or triplet states. The atomic charges , dipole moment and nuclear – nuclear repulsion energy supported the breakage bond .Also, it was found that the activation energy value for C5-H5 bond breakage is lower than that required for C8b-C5a , C5a-C5 , C5-C4 bonds which refer to C5-H5 bond in acenaphthylene molecule are weaker than C8b-C5a , C5a-C5 , C5-C4 bonds .It is reasonable to presume that C5-H5 bonds are broken first when a acenaphthylene molecule is exposed to thermal cracking. It seems that the characteristic planarity for the polyaromatic hydrocarbons is an important factor to acquire the molecule structure of the required stability along the reaction path . The trends in the bond energies and the configuration structures are discussed .

Structure and stereochemistry in 'f-block' complexes of high coordination number. VIII. The [M(unidentate)9] system. Crystal structures of [M(OH2)9] [CF3SO3]3, M = La, Gd, Lu, Y

1983 ◽  
Vol 36 (3) ◽  
pp. 483 ◽  
Author(s):  
JM Harrowfield ◽  
DL Kepert ◽  
JM Patrick ◽  
AH White
Keyword(s):  
Rare Earth ◽  
Crystal Structures ◽  
Ethyl Sulfate ◽  
Rare Earth Atom ◽  
Repulsion Energy ◽  
High Coordination Number ◽  
Tricapped Trigonal Prism ◽  
Cell Dimensions ◽  
High Coordination ◽  
The Rare Earth

The crystal structures of the nonahydrates of the rare earth trifluoromethanesulfonates, [M(OH2)9] [CF3SO3]3 have been determined at 295 K for the configurations fO, f7, f14, i.e. M = La, Gd, Lu, together with that of the yttrium analogue. The structures are similar to those of the rare earth ethyl sulfate nonahydrates, belonging to space group P6,/m (hexagonal) with cell dimensions a ≈ 13.7, c ≈ 7.5 �, Z 2, with the coordination about the rare earth atom being a tricapped trigonal prism. The structure is compared with that found from repulsion energy calculations.

Interligand repulsion energy and the twisting of hexadentate chelating ligands

1986 ◽  
Vol 25 (10) ◽  
pp. 1516-1518 ◽  
Author(s):  
Igor Gladstone ◽  
N. J. Rose ◽  
E. C. Lingafelter
Keyword(s):  
Chelating Ligands ◽  
Repulsion Energy

GROUND STATE OF THE 2D EXTENDED HUBBARD MODEL WITH MORE THAN NEAREST-NEIGHBOR INTERACTIONS

2012 ◽  
Vol 26 (29) ◽  
pp. 1250156 ◽  
Author(s):  
S. HARIR ◽  
M. BENNAI ◽  
Y. BOUGHALEB
Keyword(s):  
Phase Diagram ◽  
Hubbard Model ◽  
Ground State ◽  
State Energy ◽  
Nearest Neighbor ◽  
Finite Size ◽  
Square Lattice ◽  
Extended Hubbard Model ◽  
Eigenvalues And Eigenvectors ◽  
Repulsion Energy

We investigate the ground state phase diagram of the two dimensional Extended Hubbard Model (EHM) with more than Nearest-Neighbor (NN) interactions for finite size system at low concentration. This EHM is solved analytically for finite square lattice at one-eighth filling. All eigenvalues and eigenvectors are given as a function of the on-site repulsion energy U and the off-site interaction energy Vij. The behavior of the ground state energy exhibits the emergence of phase diagram. The obtained results clearly underline that interactions exceeding NN distances in range can significantly influence the emergence of the ground state conductor–insulator transition.

Zur Nichtlinearität der NCO-Gruppe (MO-SCF-Berechnungen an Isocyanaten III) / The Nonlinearity of the NCO-Group (MO-SCF Calculations on Isocyanates III)

1974 ◽  
Vol 29 (4) ◽  
pp. 650-652 ◽  
Author(s):  
Bernd M. Rode ◽  
Walter Kosmus ◽  
Edgar Naehbaur
Keyword(s):  
Experimental Data ◽  
Covalent Bonding ◽  
Trans Configuration ◽  
Chemical Characteristics ◽  
Cndo Method ◽  
Net Charge ◽  
Repulsion Energy ◽  
Determining Factor ◽  
Scf Calculations

The nonlinearity of the NCO group, as to be calculated after the CNDO method and in agreement with some experimental data, has been investigated systematically. The energy values, calculated for different angles, show the nuclear repulsion energy to be the determining factor for the bent (trans-) configuration of these compounds. The extent of this angle cannot be explained with classical chemical characteristics. A significant correlation is found, however, with the electronic situation at the C-atom, whose net charge and covalent bonding are likewise influenced by the NCO angle.

Systematic construction of approximate one-matrix functionals for the electron-electron repulsion energy

2002 ◽  
Vol 117 (21) ◽  
pp. 9560-9566 ◽  
Author(s):  
Jerzy Cioslowski ◽  
Katarzyna Pernal ◽  
Paul Ziesche
Keyword(s):  
Systematic Construction ◽  
Repulsion Energy ◽  
Electron Repulsion
Sign in / Sign up

Export Citation Format

Share Document