Electron Spin–Spin Contact Interaction and Mass-Variation and Darwin Relativistic Corrections in Isoelectronic Series

1972 ◽  
Vol 50 (1) ◽  
pp. 42-46
Author(s):  
B. W. N. Lo ◽  
K. M. S. Saxena ◽  
S. Fraga
Keyword(s):  
Contact Interaction ◽  
Electron Spin ◽  
Mass Variation ◽  
Total Electron ◽  
Relativistic Corrections ◽  
Isoelectronic Series

The values of the total electron spin–spin contact interaction and the mass-variation and Darwin relativistic corrections have been calculated for a number of isoelectronic series. It is observed that the main contributions to these corrections, that are not negligible, are made by the inner electrons.

Complete Electron Spin–Spin Contact Interaction in Atoms with fn Configurations

1972 ◽  
Vol 50 (9) ◽  
pp. 870-872 ◽  
Author(s):  
K. M. S. Saxena ◽  
B. W. N. Lo ◽  
S. Fraga
Keyword(s):  
Contact Interaction ◽  
Electron Spin ◽  
Ground States ◽  
Neutral Atoms ◽  
Total Electron ◽  
Hartree Fock ◽  
Positive Ions

The total electron spin–spin contact interaction, including both the inter and intrashell contributions, has been evaluated from existing numerical Hartree–Fock functions, for the ground states of the neutral atoms and doubly and triply charged positive ions from La to Yb.

Pulse Shaped Dynamic Nuclear Polarization Under Magic Angle Spinning

2019 ◽  
Author(s):  
ASIF EQUBAL ◽  
Kan Tagami ◽  
Songi Han
Keyword(s):  
Electron Spin ◽  
Lattice Relaxation ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Magic Angle ◽  
Total Electron ◽  
Spin Lattice ◽  
Maximum Benefit ◽  
Selective Saturation ◽  
Angle Spinning

In this paper, we report on an entirely novel way of improving the MAS-DNP efficiency by shaped μw pulse train irradiation for fast and broad-banded (FAB) saturation of the electron spin resonance. FAB-DNP achieved with Arbitrary Wave Generated shaped μw pulse trains facilitates effective and selective saturation of a defined fraction of the total electron spins, and provides superior control over the DNP efficiency under MAS. Experimental and quantum-mechanics based numerically simulated results together demonstrate that FAB-DNP significantly outperforms CW-DNP when the EPR-line of PAs is broadened by conformational distribution and exchange coupling. We demonstrate that the maximum benefit of FAB DNP is achieved when the electron spin-lattice relaxation is fast relative to the MAS frequency, i.e. at higher temperatures and/or when employing metals as PAs. Calculations predict that under short T<sub>1e </sub>conditions AWG-DNP can achieve as much as ~4-fold greater enhancement compared to CW-DNP.

Electron Band Structure of MnGaN

2007 ◽  
Vol 1040 ◽  
Author(s):  
Dimiter Alexandrov ◽  
Nikolaus Dietz ◽  
Ian Ferguson ◽  
Hang Yu
Keyword(s):  
Band Structure ◽  
Electron Spin ◽  
Energy Levels ◽  
Band Diagram ◽  
Total Electron ◽  
Electron Band ◽  
Hybrid Orbital ◽  
Semiconductor Alloy ◽  
Ternary Semiconductor ◽  
Electron Band Structure

AbstractInvestigation of the properties of MnxGa1-xN semiconductor alloy is performed on the basis of LCAO electron band structure of this semiconductor. The authors model this alloy on the basis of Mn substitutions on Ga sites and it is identified that the ternary semiconductor MnxGa1-xN has two tetrahedral binary constituents – GaN and MnN. It is found that the sp3 hybrid orbital of the N atom attracts an electron from the 3d orbital of the Mn atom and thus the Mn-N bonding becomes of sp3 type. In this way the total electron spin of the 3d orbital of the Mn atom becomes 3/2, which determines that the energy levels 4F, 4D, 4P and 4G belonging to this orbital to be occupied. LCAO electron band structure of wurtzite MnxGa1-xN for points Γυc1 and Γυv15 (υ = 1, 2, 3, 4, 5) is calculated by previously developed method and the positions of the levels 4F, 4D, 4P and 4G in this structure are determined. It is found dependence of the total electron spin of the Mn atom on the position of the Fermi level in the electron band diagram of MnxGa1-xN. Also it is found that the total spin depends on electron inter-band transitions as well. The optical properties of the wurtzite MnxGa1-xN are determined as well.

Electron Spin–Spin Contact Interaction in Atoms with fn Configurations

1971 ◽  
Vol 49 (15) ◽  
pp. 2031-2032 ◽  
Author(s):  
K. M. S. Saxena ◽  
B. W. N. Lo ◽  
S. Fraga
Keyword(s):  
Contact Interaction ◽  
Electron Spin ◽  
Numerical Calculations ◽  
Matrix Elements ◽  
Hartree Fock ◽  
The Matrix ◽  
Lanthanide Atoms

The expressions of the matrix elements of the electron spin–spin contact interaction have been tabulated for all the states arising from fn configurations. Numerical calculations have been carried out for a large number of lanthanide atoms and ions using accurate numerical Hartree–Fock functions.

Electron Spin-Spin Contact Interaction in Many-Electron Atoms

1969 ◽  
Vol 178 (1) ◽  
pp. 70-73 ◽  
Author(s):  
Serafin Fraga ◽  
Jon Thorhallsson
Keyword(s):  
Contact Interaction ◽  
Electron Spin

Pulse Shaped Dynamic Nuclear Polarization Under Magic Angle Spinning

2019 ◽  
Author(s):  
ASIF EQUBAL ◽  
Kan Tagami ◽  
Songi Han
Keyword(s):  
Electron Spin ◽  
Lattice Relaxation ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Magic Angle ◽  
Total Electron ◽  
Spin Lattice ◽  
Maximum Benefit ◽  
Selective Saturation ◽  
Angle Spinning

In this paper, we report on an entirely novel way of improving the MAS-DNP efficiency by shaped μw pulse train irradiation for fast and broad-banded (FAB) saturation of the electron spin resonance. FAB-DNP achieved with Arbitrary Wave Generated shaped μw pulse trains facilitates effective and selective saturation of a defined fraction of the total electron spins, and provides superior control over the DNP efficiency under MAS. Experimental and quantum-mechanics based numerically simulated results together demonstrate that FAB-DNP significantly outperforms CW-DNP when the EPR-line of PAs is broadened by conformational distribution and exchange coupling. We demonstrate that the maximum benefit of FAB DNP is achieved when the electron spin-lattice relaxation is fast relative to the MAS frequency, i.e. at higher temperatures and/or when employing metals as PAs. Calculations predict that under short T<sub>1e </sub>conditions AWG-DNP can achieve as much as ~4-fold greater enhancement compared to CW-DNP.

Mass-variation and Darwin relativistic corrections in many-electron atoms

1972 ◽  
Vol 24 (4) ◽  
pp. 300-306 ◽  
Author(s):  
B. W. N. Lo ◽  
K. M. S. Saxena ◽  
S. Fraga
Keyword(s):  
Mass Variation ◽  
Relativistic Corrections

Electron spin-spin contact interaction in many-electron atoms

1972 ◽  
Vol 24 (1) ◽  
pp. 71-77 ◽  
Author(s):  
B. W. N. Lo ◽  
K. M. S. Saxena ◽  
S. Fraga
Keyword(s):  
Contact Interaction ◽  
Electron Spin

The Three-dimensional structure of frozen-hydrated nudaurelia capensis β virus

1987 ◽  
Vol 45 ◽  
pp. 650-651
Author(s):  
N. H. Olson ◽  
T. S. Baker ◽  
Wu Bo Mu ◽  
J. E. Johnson ◽  
D. A. Hendry
Keyword(s):  
South African ◽  
Rna Virus ◽  
Carbon Film ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Electron Dose ◽  
Total Electron ◽  
Three Dimensional Structure ◽  
Negative Stain ◽  
Dimensional Reconstruction

Nudaurelia capensis β virus (NβV) is an RNA virus of the South African Pine Emperor moth, Nudaurelia cytherea capensis (Lepidoptera: Saturniidae). The NβV capsid is a T = 4 icosahedron that contains 60T = 240 subunits of the coat protein (Mr = 61,000). A three-dimensional reconstruction of the NβV capsid was previously computed from visions embedded in negative stain suspended over holes in a carbon film. We have re-examined the three-dimensional structure of NβV, using cryo-microscopy to examine the native, unstained structure of the virion and to provide a initial phasing model for high-resolution x-ray crystallographic studiesNβV was purified and prepared for cryo-microscopy as described. Micrographs were recorded ∼1 - 2 μm underfocus at a magnification of 49,000X with a total electron dose of about 1800 e-/nm2.

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