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Moseley law

Measurements of the characteristic X-ray line spectra of a number of elements were first reported by H. G. J. Moseley in 1913. He found that the square root of the frequency of the various X-ray lines exhibited a linear relationship with the atomic number of the element emitting the lines. This fundamental Moseley law shows that each element has a characteristic X-ray spectrum and that the wavelengths vary in a regular fiishion form one element to another. The wavelengths decrease as the atomic numbers of the elements increase. In addition to the spectra of pure elements, Moseley obtained the spectrum of brass, which showed strong Cu and weak Zn X-ray lines this was the first XRF analysis. The use of XRF for routine spectrochemical analysis of materials was not carried out, however, until the introduction of modern X-ray equipment in the late 1940s. [Pg.339]

The energy dependence of the emitted X-rays is a monotonically increasing function of atomic number (Moseley law). So, the position of the peaks in the spectrum is characteristic of individual elements. [Pg.549]

TABLE 1.2 Experimental Ko2 (or KL2 transition from the level L2 with =2, /= 1 and j= H to the level K with n= and /=0) X-Ray Energies, in eV, with Experimental Uncertainty in Parenthesis, as Compared with Computed Ones from the Moseley Law, for the Third and Fourth Periodic Groups of Elements (NIST 2009 Putz et al., 2010)... [Pg.29]

Finally, note that the difference between the spectral term and frequency pictures of the Moseley law is the same as that between the orbital motion frequencies and the transition frequencies between two (Bohr) levels. [Pg.29]

Moreover, the Moseley law may be regarded also as provided the atomic number Z in terms of stmctuial quantum information including spectral terms, energies, shielding constants in other words, atomic Z may be seen as a measure of such irmer quantum stmcture merely as the given constant for an atom. [Pg.30]

The American chemists employed X-ray and optical spectral techniques to study the minerals where they hoped to find element 61. Those well versed in the history of rare-earth elements could say that the path the Americans took was a troublesome one as spectral analysis not infrequently had acted as an evil genius of rare-earth studies despite all the benefits it had brought to them. But in the twenties the feet spectroscopy stood on were not so unsteady as a few decades earlier and the Moseley law could be used for predicting the X-ray spectra of any element. [Pg.209]

To trace the events now we have to go not further but some time back to the facts that were simply imknown at the time. The report of the discoverers of element 61 started with the words There had been absolutely no grounds for assuming the existence of an element between neodymium and samarium until it was demonstrated through the Moseley law. Typical dry style of a scientific report, everything would seem to be correct. But. ... ... [Pg.210]

Urbain and von Welsbach both beheved that ytterbium contained small amounts of a third rare earth that would possibly turn out to be element 72. Indeed, Urbain announced what he beheved to be a positive spectroscopic identification of element 72 in 1911, although this claim could not be confirmed by Moseley using his X-ray method. Urbain then abandoned his claim for 11 years, after which time he announced that together with Alexandre Dauvil-lier that he had used a more accurate X-ray experiment and had detected two weak lines whose firequencies corresponded approximately to those expected for element 72 on the basis of Moseleys law. But this claim, too, turned out to be unfounded. [Pg.217]

The X-ray energies of various Ka and La lines increase as a smooth function of the atomic number Z according to the Moseley law E = Zes Here n indicates the lower energy level e.g., 1 for K X-rays,... [Pg.8]

Figure 7.28 A graph of versus periodic number of a chemical element Z (Moseley law). Figure 7.28 A graph of versus periodic number of a chemical element Z (Moseley law).
The energy E of the characteristic X-rays within a given series of lines, i.e. Ka, K/J, etc., increases regularly with the atomic number Z. This dependence is called Moseley s law of X-ray emission ... [Pg.196]

Henry Moseley (1887-1915) in the laboratory in which he discovered the law named after him. [Pg.11]

Fig. 2.18. Schematic representations for discrete functions of Q-z-relationships according to natural or empirical laws (a Moseley type, b Kovats type) and empirical connections (c Colthup type, d atomic spectra type)... Fig. 2.18. Schematic representations for discrete functions of Q-z-relationships according to natural or empirical laws (a Moseley type, b Kovats type) and empirical connections (c Colthup type, d atomic spectra type)...
The characteristic X-ray wavelengths are tabulated in all standard texts on X-ray spectrometry, but can also be calculated from the atomic number of the element by Moseley s law ... [Pg.96]

Moseley s law spect The law that the square-root of the frequency of an x-ray spectral line belonging to a particular series is proportional to the difference between the atomic number and a constant which depends only on the series. mOz-lez, 10 Mossbauer spectroscopy spect The study of Mossbauer spectra, for example, for nuclear hyperfine structure, chemical shifts, and chemical analysis. mus,bau-3r spek tras ko pe ... [Pg.253]

Qualitative analysis is manifested in the identification of the elements present. It is based on Moseley s law, which points out that the energies of a pre-selected line-type (e.g. Kai) lie on a monotonic, smooth curve as a function of the atomic number. Simultaneous read-out of the positions of the many lines present in the EDS spectrum acts as identifying fingerprints and results in a list of the element present in the excited volume. [Pg.212]

A YOUNG ENGLISH SCIENTIST, HENRY MOSELEY, PERFECTED THE PERIODIC TABLE. HE DISCOVERED THE LAW OF ATOMIC NUMBERS AND ARRANGED THE ELEMENTS ACCORDING TO THE ELECTRIC CHARGE FOUND IN THE NUCLEUS. [Pg.39]

As they are caused by inner shells not involved in chemical bonding, X-ray lines are highly characteristic of a given element, and hardly shift between different compounds. Moseley s Law formed the basis of the first direct determination of the atomic numbers of elements, and was important in confirming the correct positions of elements in the periodic table. X-ray spectra are still widely used in chemical analysis, especially of solids. In an electron microscope, it is possible to excite spectra from a very small region in a solid, and thus to measure the spatial distribution of elements, and the degree of chemical homogeneity of a powdered sample. [Pg.74]

Moseley s Law suggests that the effect of electron repulsion can be represented as a screening or reduction in the real nuclear charge Ze. We write... [Pg.74]

PROBLEM 10.6.2. Show that the Kot2 emission wavelengths obtained from Table 10.3 confirm, with Moseley, the Mendeleyeff28 periodic law of the chemical elements 1/1 = K (Z-s)2, where s 3 is a shielding effect due to the other electrons in the atom. [Pg.589]


See other pages where Moseley law is mentioned: [Pg.1]    [Pg.27]    [Pg.28]    [Pg.62]    [Pg.2]    [Pg.7]    [Pg.688]    [Pg.1]    [Pg.27]    [Pg.28]    [Pg.62]    [Pg.2]    [Pg.7]    [Pg.688]    [Pg.696]    [Pg.349]    [Pg.11]    [Pg.61]    [Pg.965]    [Pg.170]    [Pg.848]    [Pg.816]    [Pg.74]    [Pg.89]    [Pg.106]    [Pg.309]    [Pg.588]   
See also in sourсe #XX -- [ Pg.339 ]

See also in sourсe #XX -- [ Pg.7 ]




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