Stark effect and line broadening in three‐dimensional stochastic fields

1973 ◽  
Vol 44 (2) ◽  
pp. 802-810 ◽  
Author(s):  
S. H. Kim ◽  
H. E. Wilhelm
Keyword(s):  
Stark Effect ◽  
Three Dimensional ◽  
Line Broadening ◽  
Stochastic Fields

Echoes and imaging in solids

1990 ◽  
Vol 333 (1632) ◽  
pp. 427-439 ◽  
Keyword(s):  
Spin Echo ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Spectral Lines ◽  
Line Broadening ◽  
Rf Pulses ◽  
Field Gradients ◽  
Magnetic Field Gradients ◽  
Bandwidth Limitation ◽  
Successful Approach

The broad spectral lines usually encountered in solid state NMR present considerable difficulties for imaging. One successful approach to the problem is to artificially narrow the line by multipulse or sample spinning methods. An alternative is to apply sufficiently large magnetic field gradients that they dominate the line broadening and seek ways to deal with bandwidth and power requirements thereby introduced. This paper explores the second route and demonstrates that spin-echo techniques help to solve several of the inherent problems. Gradient echoes produced by periodic reversal of the field gradients have significant advantages. The addition of synchronous RF pulses can produce an extended train of ‘solid’ echoes which overcomes, at least to some extent, the bandwidth limitation of this approach and permits rapid imaging in two dimensions. Slice selection and three-dimensional back projection have also been achieved in solid-like samples. Comparison with linenarrowing methods and relative advantages of the different approaches are addressed.

Re-evaluation of formulae for X-ray stress analysis in polycrystalline specimens with fibre texture: experimental confirmation

2009 ◽  
Vol 42 (5) ◽  
pp. 776-782 ◽  
Author(s):  
Ryouichi Yokoyama ◽  
Jimpei Harada ◽  
Yoshiaki Akiniwa
Keyword(s):  
Bragg Reflection ◽  
Three Dimensional ◽  
Line Broadening ◽  
Polycrystalline Specimen ◽  
X Ray ◽  
Fibre Texture ◽  
Tin Film ◽  
Biaxial Load ◽  
Measurement Direction ◽  
Film Specimen

Line splitting or line broadening of an X-ray Bragg reflection owing to a three-dimensional or biaxial load on a cubic polycrystalline specimen with 〈111〉 fibre texture has been predicted by Yokoyama & Harada [J. Appl. Cryst.(2009),42, 185–191] if the specimen is in the symmetry of the Laue classm{\overline 3}m. By using a TiN film specimen and a high-precision four-circle diffractometer with a laboratory X-ray source, it is shown that the profile of the 420 reflection is substantially different with and without biaxial load and also depends on the measurement direction, while the profile of the 222 reflection does not change. These results are quantitatively in agreement with the theoretical prediction, although the theory is based on the Reuss model of elasticity.

scholarly journals Spectral Line Broadening in Dense Plasmas

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Banaz Omar
Keyword(s):  
Spectral Line ◽  
Stark Effect ◽  
Theoretical Data ◽  
Correlation Effect ◽  
Line Broadening ◽  
Dense Plasmas ◽  
Quasistatic Approximation ◽  
Dynamic Screening ◽  
Spectral Line Broadening ◽  
Good Agreement

Spectral line broadening is calculated based on a microscopic quantum statistical approach. By using thermodynamic Green's function, plasma correlation effect, electrostatic and dynamic screening, and perturber-radiator interaction are taken into account. Ions are treated in quasistatic approximation due to Stark effect. The line broadening for 6678 Å (21P-31D) and 5016 Å (21S-31P) transitions of neutral helium is calculated in the electron density range ne=(0.25–50)×1022 m-3 and temperature range T=(0.5–4)×104 K, and the density and temperature dependence of the line width are investigated. A good agreement is shown by comparing the calculated values with the existing experimental and theoretical data.

On the theory of classical cyclotron resonance line broadening in two- and three-dimensional semiconductors

2011 ◽  
Vol 406 (22) ◽  
pp. 4283-4288
Author(s):  
S.P. Andreev ◽  
Yu. A. Gurvich ◽  
V.A. Nebogatov ◽  
T.V. Pavlova
Keyword(s):  
Cyclotron Resonance ◽  
Resonance Line ◽  
Three Dimensional ◽  
Line Broadening

scholarly journals Theoretical and experimental study of complete spectral series as a diagnostic tool for dense plasmas

1987 ◽  
Vol 5 (1) ◽  
pp. 155-162 ◽  
Author(s):  
B. d'Etat ◽  
J. Grumberg ◽  
E. Leboucher ◽  
H. Nguyen ◽  
A. Poquérusse
Keyword(s):  
Experimental Study ◽  
Diagnostic Tool ◽  
Stark Effect ◽  
High Density ◽  
Tunnel Effect ◽  
Spectral Series ◽  
Line Broadening ◽  
Dense Plasmas ◽  
Plasma Ions ◽  
Laser Plasmas

A theoretical and experimental study of line broadening and merging is presented and suggested for diagnosis of high density laser plasmas. For densities larger than 1022 cm−3 the hydrogenlike sequence is reduced to four lines for the emitter ion with ZE = 9. The perturbation effects on the latter come mainly from the interaction with plasma ions and electrons (Stark effect, multipolar interactions, ionization by tunnel effect, polarization line shift …).

Energy shift and line broadening of three-dimensional excitons in electric fields

1987 ◽  
Vol 36 (12) ◽  
pp. 6609-6612 ◽  
Author(s):  
L. Schultheis ◽  
K. Köhler ◽  
C. W. Tu
Keyword(s):  
Electric Fields ◽  
Three Dimensional ◽  
Energy Shift ◽  
Line Broadening

Evaluation of paracrystalline distortions from line broadening

1970 ◽  
Vol 26 (2) ◽  
pp. 272-277 ◽  
Author(s):  
W. Vogel ◽  
R. Hosemann
Keyword(s):  
Long Range ◽  
Three Dimensional ◽  
Quantitative Information ◽  
Cylindrical Symmetry ◽  
Range Order ◽  
Long Range Order ◽  
Line Broadening ◽  
Dimensional Lattice ◽  
Lattice Cell ◽  
Point Lattice

If the units building up a three-dimensional lattice have different sizes and/or shapes and are randomly distributed the long-range order of the point lattice is destroyed. The integral widths δb of the Debye–Scherrer lines increase quadratically with sin θ for a given set of netplanes. Studying the slopes for the reflexions h00, hh0 and hhh one obtains quantitative information on the paracrystalline distortions in the lattice. In the present paper these slopes are calculated for p.c., b.c.c. and f.c.c. lattices and identical coordination statistics with cylindrical symmetry and two fluctuation parameters α,β. The slopes can be conveniently normalized to the fluctuation Δxa of a lattice cell. In a logarithmic Δxa versus β 2/(α 2 + β 2) plot of all these types of paracrystalline lattices, observed Δxa values of manganese-rich spinels are fitted as well as possible. A body centred paracrystalline lattice is observed with α/β = 0.7 ± 0.1. This example may illustrate how to analyse reasonably paracrystalline lattices.

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