Moseley

Moseley J T 1984 Determination of ion molecular potential curves using photodissociative processes Applied Atomic Collision Physics ed H S W Massey, E W McDaniel and B Bederson (New York Academic)... 

Moseley J and Durup J 1981 Fast ion beam photofragment spectroscopy Annual Review of Physical Chemistry ed B S Rabinovitch, J M Schurr and H L Strauss (Palo Alto, CA Annual Reviews)... 

Moseley J T 1985 Ion photofragment spectroscopy Photodissociation and Photoionization ed K P Lawley (New York Wiley)... 

Moseley FI G J 1913 The high-frequency spectra of the elements Phil. Mag. 26 1024-34... 

In 1913 the English physieist Moseley examined the spectrum produced when X-rays were directed at a metal target. He found that the frequencies v of the observed lines obeyed the relationship... 

Whereas zirconium was discovered in 1789 and titanium in 1790, it was not until 1923 that hafnium was positively identified. The Bohr atomic theory was the basis for postulating that element 72 should be tetravalent rather than a trivalent member of the rare-earth series. Moseley s technique of identification was used by means of the x-ray spectra of several 2ircon concentrates and lines at the positions and with the relative intensities postulated by Bohr were found (1). Hafnium was named after Hafma, the Latin name for Copenhagen where the discovery was made. 

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. 

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 ... 

Baker, W. E., J. J. Kulesz, R. E. Richer, P. S. Westine, V. B. Parr, L. M. Vargas, and P. K. Moseley. 1978b. Workbook for Estimating the Effects of Accidental Explosions in Propellant Handling Systems. NASA CR-3023. Washington NASA Scientific and Technical Information Office. 

I9l 3 H. G. J. Moseley observed regularities in the characteristic X ray spectra of the elements he thereby discovered atomic numbers Z and provided justification for the ordina] sequence of the dements. 

Our present views on the electronic structure of atoms are based on a variety of experimental results and theoretical models which are fully discussed in many elementary texts. In summary, an atom comprises a central, massive, positively charged nucleus surrounded by a more tenuous envelope of negative electrons. The nucleus is composed of neutrons ( n) and protons ([p, i.e. H ) of approximately equal mass tightly bound by the force field of mesons. The number of protons (2) is called the atomic number and this, together with the number of neutrons (A ), gives the atomic mass number of the nuclide (A = N + Z). An element consists of atoms all of which have the same number of protons (2) and this number determines the position of the element in the periodic table (H. G. J. Moseley, 191.3). Isotopes of an element all have the same value of 2 but differ in the number of neutrons in their nuclei. The charge on the electron (e ) is equal in size but opposite in sign to that of the proton and the ratio of their masses is 1/1836.1527. 

The discovery of hafnium was one of chemistry s more controversial episodes. In 1911 G. Urbain, the French chemist and authority on rare earths , claimed to have isolated the element of atomic number 72 from a sample of rare-earth residues, and named it celtium. With hindsight, and more especially with an understanding of the consequences of H. G. J. Moseley s and N. Bohr s work on atomic structure, it now seems very unlikely that element 72 could have been found in the necessary concentrations along with rare earths. But this knowledge was lacking in the early part of the century and, indeed, in 1922 Urbain and A. Dauvillier claimed to have X-ray evidence to support the discovery. However, by that time Niels Bohr had developed his atomic theory and so was confident that element 72 would be a... 

G. J. Opiteck, J. W. Jorgenson, M. A. Moseley III and R. J. Anderegg, Two-dimensional mia ocolumn HPLC coupled to a single-quadrupole mass spectrometer for the elucidation of sequence tags and peptide mapping , 7. Microcolumn Sep. 10 365-375 (1998). 

G. J. Opiteck, S. M. Ramirez, J. W. Jorgenson and M. A. Moseley-III, Comprehensive two-dimensional liigh-performance liquid cliromatogr aphy for the isolation of overexpressed proteins andproteome mapping . Awn/. Biochem. 258 349-361 (1998). 

According lo ililler and Moseley.- chc oil contains abooc 7C per cent, of methfl-cbavicol. Traces of pinene are possibly present, but this is doubtful. Borneo] is present in -rnall quantitv. 

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