Stark shift and line broadening in three-dimensional stochastic fields of a helium plasma

1978 ◽  
Vol 44 (2) ◽  
pp. 409-422 ◽  
Author(s):  
S. H. Kim
Keyword(s):  
Three Dimensional ◽  
Stark Shift ◽  
Helium Plasma ◽  
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.

THEORETICAL STUDY OF ABOVE THRESHOLD DISSOCIATION OF HD+ IN FEMTOSECOND LASER FIELDS

2009 ◽  
Vol 08 (06) ◽  
pp. 1197-1215 ◽  
Author(s):  
KAI-JUN YUAN ◽  
ZHENG-TANG LIU ◽  
JIE YU ◽  
MAO-DU CHEN ◽  
SHU-LIN CONG
Keyword(s):  
Kinetic Energy ◽  
Femtosecond Laser ◽  
Laser Field ◽  
Three Dimensional ◽  
Stark Shift ◽  
Molecular Rotation ◽  
Photon Absorption ◽  
Intense Laser ◽  
Intense Laser Field ◽  
Linearly Polarized

The above threshold dissociation (ATD) of the HD+ molecular ion in a linearly polarized femtosecond laser field is theoretically studied using three-dimensional time-dependent quantum wave packet method. Based on the Born–Oppenheimer approximation (BOA), calculations are performed on two electronic states, the ground state 1sσ and the excited state 2pσ. The energy-dependent distributions of the dissociated fragments, resulting from the ATD, are calculated by using an asymptotic-flow expression in the momentum space. The numerical results demonstrate that, in the laser field of wavelength λ = 800 nm and full-width at half-maximum (FWHM) τ = 30 fs , only two-photon dissociation is observable at a weaker pulse peak intensity, 5.0 × 1012 W cm -2, while at an intense intensity, 1.5 × 1015 W cm -2, the dissociated fragments resulting from four-photon absorption dominates over the photodissociation process. These results are consistent with the experimental observation of Orr et al. [Orr PA et al., Phys Rev Lett98:163001, 2007]. The ac Stark-shift caused by intense laser field will change the kinetic energies of the fragments. The ATD phenomena are quantitatively interpreted in terms of the concept of light-induced potential. The molecular rotation and alignment have some effects on the kinetic energy spectrum of the dissociated fragments. The molecular rotation reduces the ac Stark-shift and broadens the peaks of kinetic energy spectra of the dissociated fragments. However, the intense laser field can effectively align the molecule and is helpful to increase the ATD probability. The ATD spectrum is related to the initial quantum numbers J0 and M0 of the molecule. The ATD spectrum of HD+ is calculated at a limited thermal temperature.

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

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.

scholarly journals Shape-Dependent Stark Shift and Emission-Line Broadening of Quantum Dots and Rings

2020 ◽  
Vol 124 (36) ◽  
pp. 19809-19816
Author(s):  
Christian Heyn ◽  
Leonardo Ranasinghe ◽  
Michael Zocher ◽  
Wolfgang Hansen
Keyword(s):  
Quantum Dots ◽  
Emission Line ◽  
Stark Shift ◽  
Line Broadening
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