The authors combine modern theoretical calculations with evaluated selected experimental data to produce a comprehensive data resource of K- and L-x-ray transition and absorption edge energies for all of the elements from neon to fermium. The theoretical and experimental components of this work are the result of programs of parallel development extending over more than 20 years. At each of several progressively more refined comparisons, it was possible to identify theoretical components whose systematic improvement then led to the next level of refinement in comparisons with an increasingly robust experimental reference data set. We have now reached a certain practical limit in what can be undertaken with reasonable levels of theoretical effort. This limit is not very different from the practical level of accuracy that can be meaningfully associated with the experimental data. For the more prominent diagram lines, experiment and theory are concordant with a zero-centered distribution of residuals whose statistical metrics allow the uncertainties to be estimated. For the light elements $(Zl20)$ and the very heavy elements $(Zg90)$ there are significant difficulties, as is also the case for a few isolated elements and transitions for $20lZl90.$ Overall, the results reported here represent improvements over previously available data compilations not only because of their scope but also because of their attempt to offer internal metrics of the database accuracy. The identified regions of difficulty are areas where further experimental work may be directed to see if there may remain theoretical issues that are still unresolved.

X-ray transition energies: new approach to a comprehensive evaluation

A method is described for the estimation of relative intensities of weak diagram lines from the microphotometer records of x-ray emission spectra registered on photographic films. The method is based on first correlating the experimentally determined relative intensities of two intense diagram lines with the theoretically calculated relative intensities. The experimental relative intensities of weak diagram lines are then interpolated to yield the corrected experimental relative intensities. These interpolated experimental relative intensities are found to be in good agreement with the theoretical relative intensities. The method has been applied to some recently reported weak lines in the L-emission spectra of the rare earth 57La to 63Eu.

Measurement of intensities of some newly observed diagram lines in the L-emission spectra of 57La to 63Eu

On the designation of some x-ray emission lines in the rare-earth elements

New diagram lines in the L emission spectrum of samarium 62

Wer Rauchringe blasen kann oder PH 3Wirbelringe zu beobachten Gelegenheit hat, weig, dab Wirbel lange Lebensdauer haben und fiber weite Strecken ziehen k6nnen und dabei ihre Substanz mitftihren. Das gilt fiir gr6Bere Wirbel in h6herem MalSe. Zyklone ziehen um die halbe Erde und ffihren die in ihnen enthaltenen Luftmengen mit sich. Hinter Hochhiiusern liegt eine ,,WirbelstraBe\" yon vielen km L~inge. Hier werden Staub, Kraftfahrzeugabgase und chemisch verdorbene Luft gleichsam als Wirbel ,,verpackt\" und ziehen in Bodenn~ihe entlang, bis sic abgekiihlt sind und damit die Tendenz zum Aufsteigen in die hohe Atmosph~ire verloren haben. Der Rand R . . . R der Wirbelstrage (Fig. la) ist f'tir Gase uniiberschreitbar; so bleibt die verschmutzte Luft der ganzen Stadt als Atemluft angeboten. Teiche und offene Schwimmb~der verschmutzen in St~idten mit Hochh~iusern schnell. Die Bewohner fliehen eine solche Stadt auch dann, wenn sie selbst nicht in Hochh~iusern wohnen. Die Hoffnung, die Stadtfliichtigen wieder zurtickholen zu k6nnen, wenn man tibliche Siedlungen zwischen den Hochh~iusern schafft, ist gering. Die nur wenige kin entfernten Hochh~iuser entwerten auch dieses Zwischengel~inde; durch HochhSluser spart man kein Gel~inde ein; man entwertet ein Vielfaches des vermeintlich eingesparten.

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New diagram lines in the L-emission spectrum of neodymium-60

The ‘s’ line in the L spectrum of 62Sm

The occurrence of a line at 2.1556 A in the L emission spectrum of cerium and two lines at 1.6679 and 1.8379 A in the L emission spectrum of samarium, reported many years ago, has remained a puzzle. These have now been identified as EXAFS minima occurring at the L absorption edges of the respective elements.

Devendra Singh

Papers

New diagram lines in the L emission spectrum of samarium 62

New diagram lines in the L-emission spectrum of neodymium-60

The ‘s’ line in the L spectrum of 62Sm

Identification of the lines in the L emission spectrum of cerium and samarium