The Mechanism of Slow Component Suppression in Lanthanum Doped Barium Fluoride Crystal

1994 ◽  
Vol 348 ◽  
Author(s):  
Gu Mu ◽  
Chen Lingyan ◽  
Li Qing ◽  
Wang Liming ◽  
Xiang Kaihua
Keyword(s):  
Electronic Structures ◽  
Cluster Model ◽  
Local Density ◽  
Slow Component ◽  
Barium Fluoride ◽  
Molecular Cluster ◽  
Entire System ◽  
Scintillation Light ◽  
Hartree Fock ◽  
Self Consistent

ABSTRACTThe electronic structures of pure BaF2 crystal and lanthanum doped BaF2 crystal have been calculated in a self-consistent molecular-cluster model. The cluster is embedded in the crystal lattice and the entire system treatediteratively in the Hartree-Fock-Slater local-density theory. As lanthanum doped BaF2 is concerned, the obtained results revealed that the F1–i which is introduced by the lanthanum may contribute to the suppression ofthe slow component in the scintillation light of BaF2 crystal.

Relation of Phase Stability Boundary to the Fill-Up Bonding States In Ni3V,Co3V and Fe3V

1990 ◽  
Vol 213 ◽  
Author(s):  
W. Lin ◽  
Jian-Hua Xu ◽  
A.J. Freeman
Keyword(s):  
Structural Stability ◽  
Electronic Structures ◽  
Local Density ◽  
Stability Boundary ◽  
The Self ◽  
Orbital Method ◽  
Density Approximation ◽  
Cohesive Properties ◽  
Self Consistent ◽  
Electronic Concentration

ABSTRACTThe electronic structures and cohesive properties of the intermetallics Ni3V, Co3V, and Fe3V in the L12 structure have been studied using the self-consistent total energy linear muffin-tin orbital method based on the local density approximation. The simple rigid-band concept appears to be adequate to explain the structural stability of these compounds. Further,the structural stability of the pseudobinary compounds (Ni,Co,Fe)3V has been investigated based on the rigid-band scheme. The correlation between the electronic concentration and the crystal structure is shown to be related to the fill-up of the bonding states.

Electronic Structure of Mercury, Gold and Platinum Impurities in Silicon

1985 ◽  
Vol 46 ◽  
Author(s):  
Jose R. Leite ◽  
Jose L.A. Alves
Keyword(s):  
Electronic Structure ◽  
Transition Metal ◽  
Valence Band ◽  
Electronic Structures ◽  
Cluster Model ◽  
Tetrahedral Site ◽  
Shallow Donor ◽  
Molecular Cluster ◽  
Vacancy Model ◽  
Isoelectronic Impurities

AbstractThe electronic structures of substitutional and tetrahedral-site interstitial Hg+, Auo and Pt− isoelectronic impurities in silicon have been analysed. The centers are theoretically described by the Watson-sphereterminated molecular cluster model within the framework of the multiplescattering Xa formalism. At the substitutional sites the centers are related to the “vacancy” model recently proposed to describe the properties of the elements at the end of the transition-metal series. At the interstitialsites the impurities introduce a hyperdeep s-like level close to the bottom of the valence band and, in agreement with experiments, do not show shallow donor activities. For all the analysed centers the d-states remain fully occupied below, or within, the valence band.

Electronic Structure of Pd doped InP

1992 ◽  
Vol 272 ◽  
Author(s):  
P. K. Khowash
Keyword(s):  
Electronic Structure ◽  
Density Of States ◽  
Cluster Model ◽  
Local Density ◽  
Energy Spectra ◽  
Valence Band Edge ◽  
Metal Impurities ◽  
Structure Of Metal ◽  
Self Consistent ◽  
Small Magnetic Moment

ABSTRACTThe electronic structure of metal impurities in III-V semiconductors are interesting because of their ability to create deep centers. We use a spin unrestricted self-consistent local density theory in a cluster model to calculate the charge distributions, one electron energy spectra and the density of states for pure InP and Pd doped InP, substituted at the In site. The pure semiconductor gap is calculated to be 1.44 eV in excellent agreement with the experimental value of 1.41 eV. A small magnetic moment of 0.561μB appears on the Pd site. The impurity introduces a levels of t2 character at 0.01 and 0.04 eV above the valence band edge.

Total Energy Calculation in α-SiO2 and β-Si3N4

1987 ◽  
Vol 105 ◽  
Author(s):  
Yongnian Xu ◽  
W. Y. Ching
Keyword(s):  
First Principles ◽  
Electronic Structures ◽  
Local Density ◽  
Energy Calculation ◽  
Atomic Orbitals ◽  
Lattice Constants ◽  
Total Energy Calculation ◽  
Self Consistent ◽  
Total Energies ◽  
Cohesive Energies

AbstractThe self-consistent electronic structures and total energies for the crystalline α-SiO2 and β-Si3N4 are studied by means of the first-principles orthogonalized linear combination of atomic orbitals method. The calculated band structures are compared with the earlier non-self consistent results. The total energies in the local density approximation are evaluated as a function of lattice parameters. Reasonable values of equilibrium lattice constants and cohesive energies are obtained but the bulk modulus for α-SiO2 is overestimated.

Self-consistent tensor effects on nuclear matter systems within a relativistic Hartree-Fock approach

2015 ◽  
Vol 91 (2) ◽  
Author(s):  
Li Juan Jiang ◽  
Shen Yang ◽  
Jian Min Dong ◽  
Wen Hui Long
Keyword(s):  
Nuclear Matter ◽  
Hartree Fock ◽  
Self Consistent

Correlation in the Ground State of He Atom

1981 ◽  
Vol 36 (3) ◽  
pp. 272-275 ◽  
Author(s):  
Subal Chandra Saha ◽  
Sankar Sengupta
Keyword(s):  
Ground State ◽  
Zero Order ◽  
Consistent Variation ◽  
Hartree Fock ◽  
Perturbation Procedure ◽  
Self Consistent ◽  
He Atom ◽  
Atomic Parameters

It is possible to reproduce the entire results of Pekeris et al. of different atomic parameters for the He atom by introducing (ll) type correlation in a self consistent variation perturbation procedure using the Hartree-Fock (HF) wavefunction as the zero-order wavefunction

Bubble Nucleation on Micro Line Heaters

2003 ◽  
Vol 125 (4) ◽  
pp. 687-692 ◽  
Author(s):  
Jung-Yeop Lee ◽  
Hong-Chul Park ◽  
Jung-Yeul Jung ◽  
Ho-Young Kwak
Keyword(s):  
Contact Angle ◽  
Free Surface ◽  
Cluster Model ◽  
Bubble Nucleation ◽  
Nucleation Temperature ◽  
Molecular Cluster ◽  
Resistance Characteristic ◽  
Nucleation Process ◽  
Superheat Limit ◽  
Current Resistance

Nucleation temperatures on micro line heaters were measured precisely by obtaining the I-R (current-resistance) characteristic curves of the heaters. The bubble nucleation temperature on the heater with 3 μm width is higher than the superheat limit, while the temperature on the heater with broader width of 5 μm is considerably less than the superheat limit. The nucleation temperatures were also estimated by using the molecular cluster model for bubble nucleation on the cavity free surface with effect of contact angle. The bubble nucleation process was observed by microscope/35 mm camera unit with a flash light of μs duration.

Ab Initio Study of Electronic Structure of RDX Molecular Crystal

1992 ◽  
Vol 296 ◽  
Author(s):  
Guang Gao ◽  
Ravindra Pandey ◽  
A. Barry Kunz
Keyword(s):  
Electronic Structure ◽  
Hot Spots ◽  
Molecular Crystal ◽  
Perfect Crystal ◽  
Local Region ◽  
Molecular Cluster ◽  
Ab Initio Study ◽  
Hartree Fock ◽  
Cyclotrimethylene Trinitramine ◽  
Defective Crystal

AbstractAn embedded molecular cluster model is used to study the electronic structure of cyclotrimethylene trinitramine(RDX) molecular crystal. In this model, a molecular cluster describing a local region of the crystal is treated in the Hartree-Fock approximation. The embedding lattice is represented by multipoles that are determined quantum-mechanically. Cluster-lattice orthogonality is achieved by transforming canonical orbitals to orbitals which are localized on individual molecular sites by means of a self-consistent localization potential. Results for the free molecule and the perfect crystal demonstrate the domination of three N-NO2 groups on intermolecular properties. For the defective crystal, results show a significant distortion in the electronic structure caused by local deformations in the lattice that may account for the formation of hot spots.

scholarly journals RELATIVE MOTION CORRECTION TO FISSION BARRIERS

2008 ◽  
Vol 17 (01) ◽  
pp. 151-159 ◽  
Author(s):  
J. SKALSKI
Keyword(s):  
Relative Motion ◽  
Cluster Model ◽  
Motion Correction ◽  
Mean Field Theory ◽  
Mean Field ◽  
Ternary Fission ◽  
Skyrme Interaction ◽  
Hartree Fock ◽  
Fission Barriers ◽  
The Mean

We discuss the effect of kinetic energy of the relative motion becoming spurious for separate fragments on the selfconsistent mean-field fission barriers. The treatment of the relative motion in the cluster model is contrasted with the necessity of a simpler and approximate approach in the mean-field theory. A scheme of the energy correction to the Hartree-Fock is proposed. The results obtained with the effective Skyrme interaction SLy 6 show that the correction, previously estimated as ~ 8 MeV in A = 70 - 100 nuclei, amounts to 4 MeV in the medium heavy nucleus 198 Hg and to null in 238 U . However, the corrected barrier implies a shorter fission half-life of the latter nucleus. The same effect is expected to lower barriers for multipartition (i.e. ternary fission, etc) and make hyperdeformed minima less stable.

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