Modified Atomic Orbital Method. II. The Electronic Structure of the Oxygen Molecule

1956 ◽  
Vol 25 (6) ◽  
pp. 1098-1101 ◽  
Author(s):  
Takashi Itoh ◽  
Kimio Ohno
Keyword(s):  
Electronic Structure ◽  
Atomic Orbital ◽  
Oxygen Molecule ◽  
Orbital Method

A semi-empirical molecular orbital scheme to study electron transfer in iron–sulphur proteins

2005 ◽  
Vol 33 (1) ◽  
pp. 20-21 ◽  
Author(s):  
M. Sundararajan ◽  
J.P. McNamara ◽  
M. Mohr ◽  
I.H. Hillier ◽  
H. Wang
Keyword(s):  
Electron Transfer ◽  
Electronic Structure ◽  
Molecular Orbital ◽  
Parametric Method ◽  
Orbital Method ◽  
Molecular Orbital Method ◽  
Semi Empirical

We describe the use of the semi-empirical molecular orbital method PM3 (parametric method 3) to study the electronic structure of iron–sulphur proteins. We first develop appropriate parameters to describe models of the redox site of rubredoxins, followed by some preliminary calculations of multinuclear iron systems of relevance to hydrogenases.

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.

The electronic structure of polymers by the FSGO (Floating Spherical Gaussian Orbital) method

1980 ◽  
Vol 57 (1) ◽  
pp. 43-51 ◽  
Author(s):  
David R. Armstrong ◽  
John Jamieson ◽  
Peter G. Perkins
Keyword(s):  
Electronic Structure ◽  
Orbital Method ◽  
Gaussian Orbital

Use of Replaced Chalcones to Generate a 13C Chemical Shift Staging Factor for Chalcone and Its Derivate

2020 ◽  
Vol 12 (4) ◽  
pp. 464-472
Author(s):  
Thaís F. Giacomello ◽  
Gunar V. da S. Mota ◽  
Antônio M. de J. C. Neto ◽  
Fabio L. P. Costa
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Density Functional ◽  
Chemical Shifts ◽  
Atomic Orbital ◽  
Scaling Factor ◽  
Orbital Method ◽  
Beneficial Effects ◽  
Nuclear Magnetic

Chalcones have attracted the attention of researchers for decades, they are biologically classified as secondary metabolites of low molecular weight. These are considered as the precursors of flavonoids and they are widely distributed in plants such as vegetables, fruits, teas and spices. It has been demonstrating that chalcones possess many important bioactivities including properties of antioxidants and other evidence of its potential beneficial effects on health. Chalcone compounds and its derivatives have been showing a growing interest in the therapeutic properties. Nuclear magnetic resonance (NMR) spectroscopy is one of the most important tools for determining the structures of organic molecules. In the work present a 13C Nuclear magnetic resonance chemical shift protocol of chalcones and derivative based on the application of scaling factor with chalcone molecules. This protocol consists of using density functional theory with gauge-including atomic orbital method to calculating 13C chemical shifts and the application of a parameterized scaling factor in order to ensure accurate structural determination of chalcones and derivative.

FUSION RATE IN μtt IN MUONIC MOLECULAR ION USING LINEAR COMBINATION OF ATOMIC ORBITAL METHOD

2011 ◽  
Vol 20 (03) ◽  
pp. 629-636
Author(s):  
M. MAHDAVI ◽  
B. KALEJI ◽  
T. KOOHROKHI
Keyword(s):  
Reaction Rate ◽  
Transition Probability ◽  
Atomic Orbital ◽  
Fusion Reaction ◽  
Fusion Cross Section ◽  
Nuclear Interaction ◽  
Fusion Rate ◽  
Nuclear Potential ◽  
Orbital Method ◽  
Molecular Ion

In this paper, the tritium–tritium fusion reaction rate in a muonic molecular ion (μtt) is calculated by using a square-well nuclear potential as a complex for nuclear interaction between two tritones. The complex potential parameters are obtained by fitting process on fusion cross-section experimental data. The real and imaginary parts of the nuclear potential are calculated as Ur = -62531.87 (keV) and Ui = -165.63 (keV), respectively. A free parameter that is related to the radius of this potential is A = 0.004155. Also, considering the optical nuclear potential, the energy value of μtt muonic molecular ion is calculated. The fusion rate is calculated by liner combination of atomic orbital (LCAO) method. Finally, the reaction rate, λ, is obtained 0.28×1010 s -1 by calculating the transition probability through the potential barrier and the oscillation frequency of wave function.

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