Limitations of Global Hybrids in Predicting the Geometries and Torsional Energy Barriers of Dimeric Systems and the Role of Hartree Fock and DFT Exchange

2019 ◽  
Vol 40 (32) ◽  
pp. 2810-2818
Author(s):  
Talapunur Vikramaditya ◽  
Shiang‐Tai Lin
Keyword(s):  
Energy Barriers ◽  
Hartree Fock ◽  
Torsional Energy

Insights into the synergistic role of metal–lattice oxygen site pairs in four-centered C–H bond activation of methane: the case of CuO

2016 ◽  
Vol 6 (11) ◽  
pp. 3984-3996 ◽  
Author(s):  
Jithin John Varghese ◽  
Quang Thang Trinh ◽  
Samir H. Mushrif
Keyword(s):  
Activation Energy ◽  
Copper Oxide ◽  
Bond Activation ◽  
Lattice Oxygen ◽  
Oxide Surfaces ◽  
Energy Barriers ◽  
Metal Lattice ◽  
Oxygen Site ◽  
Site Pair

Of the three mechanisms for activation of methane on copper and copper oxide surfaces, the under-coordinated Cu–O site pair mediated mechanism on CuO surfaces has the lowest activation energy barriers.

Microscopic description of the fusion excitation function of 32,36S+90,94,96Zr

2020 ◽  
Vol 29 (07) ◽  
pp. 2050046
Author(s):  
M. Rashdan ◽  
T. A. Abdel-Karim
Keyword(s):  
Excitation Function ◽  
Excited States ◽  
Density Functional ◽  
Neutron Density ◽  
Energy Density Functional ◽  
Hartree Fock ◽  
Density Distributions ◽  
Text Interaction ◽  
Good Agreement

The fusion excitation function for the systems [Formula: see text]S+[Formula: see text]Zr is investigated using a microscopic internuclear potential derived from Skyrme energy density functional. The inputs in this approach are the proton and neutron density distributions of the interacting nuclei, which are derived from Skyrme–Hartree–Fock calculations. The SkM[Formula: see text] interaction is used in the calculation of the nuclear densities as well as the internuclear potential. The coupling to low lying inelastic excited states of target and projectile is considered. The role of the neutron transfer is discussed, where it is considered through the CCFULL model calculation. A good agreement with the experimental data is obtained without adjustable parameters.

From Atomic Orbitals to Molecular Orbitals and Chemical Bonds

2020 ◽  
pp. 150-187
Author(s):  
Jochen Autschbach
Keyword(s):  
Hydrogen Molecule ◽  
Atomic Orbital ◽  
Plane Waves ◽  
Basis Set ◽  
Orbital Method ◽  
Chemical Bonds ◽  
Atomic Orbitals ◽  
Hartree Fock ◽  
Generalized Matrix

It is shown how an aufbau principle for atoms arises from the Hartree-Fock (HF) treatment with increasing numbers of electrons. The Slater screening rules are introduced. The HF equations for general molecules are not separable in the spatial variables. This requires another approximation, such as the linear combination of atomic orbitals (LCAO) molecular orbital method. The orbitals of molecules are represented in a basis set of known functions, for example atomic orbital (AO)-like functions or plane waves. The HF equation then becomes a generalized matrix pseudo-eigenvalue problem. Solutions are obtained for the hydrogen molecule ion and H2 with a minimal AO basis. The Slater rule for 1s shells is rationalized via the optimal exponent in a minimal 1s basis. The nature of the chemical bond, and specifically the role of the kinetic energy in covalent bonding, are discussed in details with the example of the hydrogen molecule ion.

scholarly journals Hydrogen diffusion out of ruthenium—an ab initio study of the role of adsorbates

2020 ◽  
Vol 22 (15) ◽  
pp. 7935-7941
Author(s):  
Chidozie Onwudinanti ◽  
Geert Brocks ◽  
Vianney Koelman ◽  
Thomas Morgan ◽  
Shuxia Tao
Keyword(s):  
Ab Initio ◽  
Hydrogen Diffusion ◽  
Ab Initio Study ◽  
Energy Barriers ◽  
Near Surface

The energy barriers to hydrogen diffusion from near-surface interstitial sites in ruthenium are determined by the presence of adsorbates.

scholarly journals Comparison between the Thomas–Fermi and Hartree–Fock–Bogoliubov Methods in the Inner Crust of a Neutron Star: The Role of Pairing Correlations

Universe ◽  
2020 ◽  
Vol 6 (11) ◽  
pp. 206
Author(s):  
Matthew Shelley ◽  
Alessandro Pastore
Keyword(s):  
Neutron Star ◽  
Mean Field ◽  
Pairing Correlation ◽  
Field Methods ◽  
Density Region ◽  
Thomas Fermi ◽  
Hartree Fock ◽  
Pairing Correlations ◽  
Mean Field Methods

We investigated the role of a pairing correlation in the chemical composition of the inner crust of a neutron star with the extended Thomas–Fermi method, using the Strutinsky integral correction. We compare our results with the fully self-consistent Hartree–Fock–Bogoliubov approach, showing that the resulting discrepancy, apart from the very low density region, is compatible with the typical accuracy we can achieve with standard mean-field methods.

scholarly journals THE GAMOW-TELLER RESPONSE IN DEFORMED NUCLEI

2006 ◽  
Vol 15 (07) ◽  
pp. 1397-1406 ◽  
Author(s):  
P. SARRIGUREN ◽  
R. ÁLVAREZ-RODRÍGUEZ ◽  
O. MORENO ◽  
E. MOYA DE GUERRA
Keyword(s):  
Nuclear Astrophysics ◽  
Double Beta Decay ◽  
Β Decay ◽  
Hartree Fock ◽  
Decay Properties ◽  
Medium Mass ◽  
Deformation Dependence ◽  
Gamow Teller ◽  
Strength Distributions

We study Gamow-Teller strength distributions within a QRPA approach performed on top of a deformed Skyrme-Hartree-Fock+BCS single particle basis with the inclusion of residual spin-isospin interactions in both particle-hole and particle-particle channels. We focus our attention in several problems of interest in Nuclear Structure and Nuclear Astrophysics, such as the β-decay properties of proton-rich medium-mass nuclei of astrophysical interest and the deformation dependence of the Gamow-Teller strength distributions in neutron deficient Pb isotopes. We also discuss the role of deformation in the two-neutrino double beta decay.

On the role of the termolecular reactions 2O2 + H2 → 2HO2 and 2O2 + H2 → H + HO2 + O2 in formation of the first radicals in hydrogen combustion: ab initio predictions of energy barriers

2017 ◽  
Vol 19 (3) ◽  
pp. 2175-2185 ◽  
Author(s):  
M. Monge-Palacios ◽  
Homayoon Rafatijo
Keyword(s):  
Ab Initio ◽  
Barrier Height ◽  
Hydrogen Combustion ◽  
Initial Reaction ◽  
Energy Barriers

We have identified a new initial reaction in hydrogen combustion with a low barrier height and thus competitive: 2O2 + H2 → 2HO2.

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