scholarly journals THEORETICAL TREATMENT OF RADIATION TRAPPING OF ATOMIC FLUORESCENCE IN V-E ENERGY TRANSFER

1998 ◽  
Vol 47 (2) ◽  
pp. 198
Author(s):  
WANG CHU-JI ◽  
WANG JIAN ◽  
MA XING-XIAO
Keyword(s):  
Energy Transfer ◽  
Theoretical Treatment ◽  
Atomic Fluorescence ◽  
Radiation Trapping

Sensitized Liquid Phase Room Temperature Phosphorescence Applied to the Detection of Polychloronaphthalenes: The Influence of the Reversed Energy Transfer Reaction on the Linearity

1983 ◽  
Vol 37 (2) ◽  
pp. 188-192 ◽  
Author(s):  
J. J. Donkerbroek ◽  
A. C. Veltkamp ◽  
A. J. J. Praat ◽  
C. Gooijer ◽  
R. W. Frei ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Liquid Phase ◽  
Triplet State ◽  
Room Temperature ◽  
Transfer Reaction ◽  
Detection Limits ◽  
Theoretical Treatment ◽  
Quantitative Interpretation ◽  
Room Temperature Phosphorescence

The detection of a series of polychloronaphthalenes (PCN's), i.e., mono-, di-, tri-, and tetra-substituted compounds, via sensitized room temperature phosphorescence of biacetyl in azeotropic acetonitrile/water is investigated. The detection limits are on the order of 10−8 to 10−9 M, except for 1,2,3-trichloro- and 1,2,3,4-tetrachloronaphthalene, and are comparable to those we obtained with fluorescence. Phosphorescence measurements at 77 K reveal that, with the exception of 1,2,3-trichloronaphthalene, for the tri- and tetra-substituted compounds the triplet state energies are lower than for biacetyl. Hence, for these PCN's the influence of the reversed energy transfer on the sensitized RTPL (room temperature phosphorescence in liquids) detection must be considered. On the basis of a theoretical treatment it is demonstrated that the reversed energy transfer manifests itself mainly via the linearity of the response. Furthermore, it is shown that the parameters needed for a quantitative interpretation of the results can be deduced from measurements of the direct phosphorescence of biacetyl.

scholarly journals THEORETICAL TREATMENT OF RADIATION TRAPPING IN A MULTIPLE LINES COUPLED SYSTEM

1997 ◽  
Vol 46 (1) ◽  
pp. 42
Author(s):  
LAI RE ◽  
WANG JIAN ◽  
WANG CHU-JI ◽  
MA XING-XIAO
Keyword(s):  
Coupled System ◽  
Theoretical Treatment ◽  
Radiation Trapping

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Contrasts of planar defects in reflection electron microscopy

1993 ◽  
Vol 51 ◽  
pp. 1004-1005
Author(s):  
Feng Tsai ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Surface Defects ◽  
Practical Importance ◽  
Theoretical Treatment ◽  
Crystal Surfaces ◽  
Planar Defects ◽  
Surface Steps ◽  
Surface Reconstructions ◽  
Domain Boundaries ◽  
Reflection Electron Microscopy

Reflection electron microscopy (REM) has been used to study surface defects such as surface steps, dislocations emerging on crystal surfaces, and surface reconstructions. However, only a few REM studies have been reported about the planar defects emerging on surfaces. The interaction of planar defects with surfaces may be of considerable practical importance but so far there seems to be only one relatively simple theoretical treatment of the REM contrast and very little experimental evidence to support its predications. Recently, intersections of both 90° and 180° ferroelectric domain boundaries with BaTiO3 crystal surfaces have been investigated by Tsai and Cowley with REM.The REM observations of several planar defects, such as stacking faults and domain boundaries have been continued by the present authors. All REM observations are performed on a JEM-2000FX transmission electron microscope. The sample preparations may be seen somewhere else. In REM, the incident electron beam strikes the surface of a crystal with a small glancing angle.

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