Interpretation of Changes in Shape of K Emission Bands of Light Elements with Chemical Combination

Author(s):  
J. E. Holliday

A large amount of experimental work has been done to show an effect of chemical combination on X-ray absorption edges. After the first attempt of Wentzel, Kossel and others, and still more recently Pauling, have tried to explain the effect; but at the present time it remains far from being clearly understood. The question must be attacked from the side of the emission spectrum also. About the year 1923 Lindh and Lundquist in Professor seigbahn's laboratory at Lund showed an influence of chemical combination on the wave-lengths and structure of the β lines of phosphorus, sulphur and chlorine. Later Bäcklin and Ray showed an effect of chemical combination on the Kα doublet of some light elements. Most surprising shifts in the positions of the components of the doublet were then observed. Recently Lundquist has studied the Kβ group of sulphur in different chemical compounds of this element. This author finds that no other line except β 1 and β x is emitted by any of the compounds. It is interesting to note that Hjalmar has definitely listed a third line β 3 for sulphur. The following investigation was therefore taken up to clarify this point. As will be seen, some interesting facts regarding this question have been brought to light.


Author(s):  
R. H. Duff

A material irradiated with electrons emits x-rays having energies characteristic of the elements present. Chemical combination between elements results in a small shift of the peak energies of these characteristic x-rays because chemical bonds between different elements have different energies. The energy differences of the characteristic x-rays resulting from valence electron transitions can be used to identify the chemical species present and to obtain information about the chemical bond itself. Although these peak-energy shifts have been well known for a number of years, their use for chemical-species identification in small volumes of material was not realized until the development of the electron microprobe.


Author(s):  
T. Oikawa ◽  
M. Inoue ◽  
T. Honda ◽  
Y. Kokubo

EELS allows us to make analysis of light elements such as hydrogen to heavy elements of microareas on the specimen. In energy loss spectra, however, elemental signals ride on a high background; therefore, the signal/background (S/B) ratio is very low in EELS. A technique which collects the center beam axial-symmetrically in the scattering angle is generally used to obtain high total intensity. However, the technique collects high background intensity together with elemental signals; therefore, the technique does not improve the S/B ratio. This report presents the experimental results of the S/B ratio measured as a function of the scattering angle and shows the possibility of the S/B ratio being improved in the high scattering angle range.Energy loss spectra have been measured using a JEM-200CX TEM with an energy analyzer ASEA3 at 200 kV.Fig.l shows a typical K-shell electron excitation edge riding on background in an energy loss spectrum.


Author(s):  
G.F. Bastin ◽  
H.J.M. Heijligers

Among the ultra-light elements B, C, N, and O nitrogen is the most difficult element to deal with in the electron probe microanalyzer. This is mainly caused by the severe absorption that N-Kα radiation suffers in carbon which is abundantly present in the detection system (lead-stearate crystal, carbonaceous counter window). As a result the peak-to-background ratios for N-Kα measured with a conventional lead-stearate crystal can attain values well below unity in many binary nitrides . An additional complication can be caused by the presence of interfering higher-order reflections from the metal partner in the nitride specimen; notorious examples are elements such as Zr and Nb. In nitrides containing these elements is is virtually impossible to carry out an accurate background subtraction which becomes increasingly important with lower and lower peak-to-background ratios. The use of a synthetic multilayer crystal such as W/Si (2d-spacing 59.8 Å) can bring significant improvements in terms of both higher peak count rates as well as a strong suppression of higher-order reflections.


1991 ◽  
Vol 161 (5) ◽  
pp. 171-175 ◽  
Author(s):  
Yu.B. Khariton ◽  
Ya.B. Zeldovich ◽  
I.I. Gurevich ◽  
I.Ya. Pomeranchuk

1947 ◽  
Author(s):  
H. Schlesinger ◽  
G. W. Schaeffer
Keyword(s):  

1998 ◽  
Vol 499 (2) ◽  
pp. 735-745 ◽  
Author(s):  
Martin Lemoine ◽  
Elisabeth Vangioni‐Flam ◽  
Michel Casse

2021 ◽  
Vol 52 (1) ◽  
pp. 1088-1090
Author(s):  
Jae Bum HAN ◽  
Young-Gil Park ◽  
Soo Im Jeong ◽  
Nari Ahn

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 33
Author(s):  
Valérie Laperche ◽  
Bruno Lemière

Portable X-ray fluorescence spectroscopy is now widely used in almost any field of geoscience. Handheld XRF analysers are easy to use, and results are available in almost real time anywhere. However, the results do not always match laboratory analyses, and this may deter users. Rather than analytical issues, the bias often results from sample preparation differences. Instrument setup and analysis conditions need to be fully understood to avoid reporting erroneous results. The technique’s limitations must be kept in mind. We describe a number of issues and potential pitfalls observed from our experience and described in the literature. This includes the analytical mode and parameters; protective films; sample geometry and density, especially for light elements; analytical interferences between elements; physical effects of the matrix and sample condition, and more. Nevertheless, portable X-ray fluorescence spectroscopy (pXRF) results gathered with sufficient care by experienced users are both precise and reliable, if not fully accurate, and they can constitute robust data sets. Rather than being a substitute for laboratory analyses, pXRF measurements are a valuable complement to those. pXRF improves the quality and relevance of laboratory data sets.


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