Magnetic anisotropy ofR2Fe14B(R=Nd, Gd, Y): Density functional calculation by using the linear combination of pseudo-atomic-orbital method

2010 ◽  
Vol 81 (21) ◽  
Author(s):  
Isao Kitagawa ◽  
Yusuke Asari
Keyword(s):  
Magnetic Anisotropy ◽  
Linear Combination ◽  
Density Functional ◽  
Atomic Orbital ◽  
Orbital Method ◽  
Density Functional Calculation

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.

ELECTRONIC AND OPTICAL PROPERTIES OF NITROGEN DOPED SiC NANOCRYSTALS: FIRST PRINCIPLES STUDY

2013 ◽  
Vol 27 (13) ◽  
pp. 1350053 ◽  
Author(s):  
MASOUD BEZI JAVAN
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Nitrogen Atom ◽  
First Principles ◽  
Density Functional ◽  
High Probability ◽  
Atomic Orbital ◽  
Density Functional Calculation ◽  
Hydrogen Atoms ◽  
Nitrogen Doped

A typical nitrogen doped spherical SiC nanocrystal with a diameter of 1.2 nm ( Si 43 C 44 H 76) using linear combination atomic orbital (LCAO) in combination with pseudopotential density functional calculation have been studied. Our selected SiC nanocrystal has been modeled taking all the cubic bulk SiC atoms contained within a sphere of a given radius and terminating the surface dangling bonds with hydrogen atoms. We have examined nine possible situations in which nitrogen has a high probability for replacement in the lattice or placed between atoms in the nanocrystal. We have found that the silicone can substitute with a nitrogen atom in each layer as the constructed nanocrystals remain thermodynamically stable. Also the nitrogen atom can be placed between the free atomic spaces as the more thermodynamically stable position of the nitrogen is between the topmost layers. Also the optical absorption and refractive index energy dispersions of the pure and various stable doped SiC nanocrystals were studied.

Density Functional Calculation of Property of the (1 0 0) Surface of γ-Pu

2010 ◽  
Author(s):  
Rusong Li ◽  
Bin He ◽  
Quanhu Zhang ◽  
Qianwei Du
Keyword(s):  
Fermi Level ◽  
Density Functional ◽  
Atomic Orbital ◽  
Relativistic Effects ◽  
Local Property ◽  
Density Functional Calculation ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Surface Corrosion ◽  
Generate Surface

Pu material can generate surface corrosion and self-radiation effect during storage, leading to the creation and recoil of uranium and helium ions, which produce defects through displacement cascades, these self-irradiation defects tend to change plutonium properties. To study these aging behavior, calculations at the spin unrestricted generalized gradient approximation (GGA) level of density functional theory (DFT) have been performed using the DMol3 programs. Relativistic effects, such as mass-velocity, Darwin term, are considered in this code. Some conclusions are draw as follows: 1) Band structure of the (100) surface of γ-Pu is very narrow around the Fermi level, showing that the eigenstate of this level is mainly composed of local atomic orbital, the local property of electrons in this band is very strong, while the band around the Fermi level is mainly constituted by 5f narrow band; 2) DOS of the (100) surface of γ-Pu are mainly composed of the density of states in −48–41eV, −23–16eV, −3–2eV; 3) Contribution of s shell to the total DOS is mainly distributed in the first interval, and p shell is mainly in the second interval, while d and f shells are mainly in the third interval.

A theoretical study of the 77Se NMR and vibrational spectroscopic properties of SenS8–n ring molecules

2002 ◽  
Vol 80 (11) ◽  
pp. 1435-1443 ◽  
Author(s):  
J Komulainen ◽  
R S Laitinen ◽  
R J Suontamo
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Chemical Shifts ◽  
Atomic Orbital ◽  
Geometry Optimization ◽  
Spectroscopic Properties ◽  
Basis Sets ◽  
Orbital Method ◽  
Hybrid Functional ◽  
Ring Molecules

The structures and spectroscopic properties of SenS8–n ring molecules have been studied by the use of ab initio molecular orbital techniques and density functional techniques involving Stuttgart relativistic large core effective core potential approximation with double zeta basis sets for valence orbitals augmented by two polarization functions for both sulfur and selenium. Full geometry optimizations have been carried out for all 30 isomers at the Hartree-Fock level of theory. The optimized geometries and the calculated fundamental vibrations and Raman intensities of the SenS8–n molecules agree closely with experimental information where available. The nuclear magnetic shielding tensor calculations have been carried out by the Gauge-independent atomic orbital method at the DFT level using Becke's three-parameter hybrid functional with Perdew/Wang 91 correlation. The isotropic shielding tensors correlate well with the observed chemical shift data. The calculated chemical shifts provide a definite assignment of the observed 77Se NMR spectroscopic data and can be used in the prediction of the chemical shifts of unknown SenS8–n ring molecules.Key words: selenium sulfides, ab initio, DFT, effective core potentials, geometry optimization, energetics, fundamental vibrations, 77Se chemical shifts.

Anisotropic gap of superconductingCaC6: A first-principles density functional calculation

2007 ◽  
Vol 75 (2) ◽  
Author(s):  
A. Sanna ◽  
G. Profeta ◽  
A. Floris ◽  
A. Marini ◽  
E. K. U. Gross ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Density Functional Calculation
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