Extended X‐ray absorption fine structure (EXAFS) studies of the lanthanides

Vijayavargiya, V. P.; Gupta, Shuchi; Padalia, B. D.

doi:10.1002/pssb.2220800109

Cited by 16 publications

(4 citation statements)

References 16 publications

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“…Further, the L3 absorption curves of R in RCu2Si2 and RCu2Ge2 (R = Gd, Tb, Dy, Ho and Tm) shown in figures 2 and 4 exhibit splitting into two components, L3 and LS . It is noted that the shape of the L3 absorption curves for RCu2Si2 and RCu2Ge2 (figures 2 and 4) resemble closely those reported for the corresponding rare-earth metals (Vijayavargiya 1977). However, splitting of the L3 edge is not detected for the lighter rare earths, Pr, Nd and Sm.…”

Section: B D Padalia T K Hahvar and M N Ghatikarsupporting

confidence: 74%

Studies of the kinetics of the vibrational and rotational distribution functions of nitrogen excited by a pulsed discharge

Valyanskiĭ¹,

Vereschagin²,

Vernke³

et al. 1984

Sov. J. Quantum Electron.

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LJ absorption edges of rare earths. R , in RCu& (except for R = La. Ce, Eu. Er and Lu) and in RCu2Ge2 (except for R = La. Ce, Er and Lu) intermetallic compounds are recorded. Shifts in energy of the L? edge in these systems with respect to corresponding rare-earth metal edge position are measured. It is found that the rare-earth ions exist in a trivalent state except for Eu and Yb. The divalent state of Eu in EuCu2GeZ and that of Yb in YbCuzGe2 are established. Shifts in energy of the K absorption edge of Cu in RCuZSi2 and RCu2Ge2 (except for Ho and Lu) are also measured. The present results on the Kedge shifts of Cu in RCu2GeZ and RCu2Si2 are. in general, consistent with the available NMR measurements on the same systems.

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Section: B D Padalia T K Hahvar and M N Ghatikarsupporting

confidence: 74%

Studies of the kinetics of the vibrational and rotational distribution functions of nitrogen excited by a pulsed discharge

Valyanskiĭ¹,

Vereschagin²,

Vernke³

et al. 1984

Sov. J. Quantum Electron.

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“…X-ray absorption spectroscopic studies carried out in our laboratory have furnished useful information about the unoccupied 4f and 5d states above Fernii level in the heavy rare earth metals [ 1, 21. Recently, the extended X-ray absorption fine strnct'ures (EXAFS) for these metals were reported [3]. We report in this papcr the results of the investigation on the EXAFS and chemical shifts for the piire oxide samples,…”

Section: Introductionmentioning

confidence: 97%

Extended X‐Ray Absorption Fine Structures and Chemical Shifts for the Heavy Rare‐Earth Oxides

Gupta

Vijayavargiya²,

Padalia

et al. 1977

Physica Status Solidi (b)

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L,-absorption edges and the associated extended X-ray absorption fine structures (EXAFS) for dysprosium, holmium, thulium, ytterbium, and lutetium in pure oxide form are investigated using a 600 mm curved crystal spectrograph. A forbidden transition corresponding to an electron transition, 2~312 + 4f (unoccupied), is detected for Dy,O,, Ho,O,, and Tm,O, with open 4f-shell.Chemical shifts are measured and an attempt made to correlate these with the estimated effective charges on the ions indicates a new trend not reported by others. A prominent absorption peak, A (white line), is also recorded for the oxides. The reduced width of these white lines for oxides indicates the narrowing of the 5d band. The metal-oxygen distances determined using EXAFS methods agree with the crystallographic data. Shapes of the EXAFS for oxides resemble with each other while they differ from those recorded for the corresponding metals.Die L,-Absorptionskanten und die verknupften ansgedehnten Rontgenabsorptionsfeinstrukturen (EXAFS) fur Dysprosium, Holmium, Thulium, Ytterbium and Lutetium in reiner Oxidform werden mit einem gebogenen 600 mm-Kristallspektrographen untersucht. Es wird ein verbotener fibergang entsprechend oinem elektronischen Ubergang, 2p3/2 -4f (unbesetzt), fiir Dy,O,, Ho,O, und Tm,O, mit offener 4f-Schale cntdeckt. Chemische Verschiebungen werden gemessen und der Versuch, diese mit berechneten effektiven Ladungen a n den Ionen zu korrelieren, ergibt einen neuen Trend der bisher noch nicht veroffentlicht wurde. Ein herausragendes Absorptionsmaximiim A (wei5e Linie) wird ebenfalls fur die Oxide gefunden. Die rednzierte Breite dieser wei5en Linien fur Oxide zeigt die Verschmalerung der 5d-Bande. Die mit den EXSFS-Methoden bcstimmten Metall-Sauerstoff-Abstande stimmen mit krist>allographischen IVerten ubcrein. Die Form der EXAFS fur Oxide stimmen untereinander uberein, wahrend sie sich 17011 denen unterscheiden, die fur die entsprechenden Metalle bestimmt werdeu.

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“…the slope of the graph of f&b(k) veIsus k. The estimated values of a(") for rare earth metals, the oxides R,O,, and the intermetallic compounds RMn, are given in Table 1. The measured energies of the maxima and minima associated with the L,-absorption edge of rare earths in metals [7], R,O, compounds IS], and RMn, intermetallics [9] have been used to determine the values of a(E) and are included in Table 1. I n the case of Cu metal the calculated theoretical phase shift, qa.b(k), is plotted as a function of k (Fig.…”

Section: Resultsmentioning

confidence: 99%

Chemical Transferability of Phase Shifts in Extended X‐Ray Absorption Fine Structure

Ghatikar

1983

Physica Status Solidi (b)

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The empirical phase shifts are calculated from the theoretical X-ray absorption fine structure phase functions in a large number of systems with different atom-pairs in varying surroundings. Measured extended X-ray absorption fine structure (EXAFS) data are used to estimate the linearly dependent term on k in the phase shift and to compare it with theoretical values. Attempts are made to explain the behaviour of the phase shift of a given atom-pair in different chemical surroundings and for different atom-pairs in a given isoelectronic series of elements.Es werden die empirischen Phasenverschiebungen einer grol3en Anzahl von Systemen mit unterschiedlichen Atompaaren mit veriinderlichen Umgebungen aus den theoretischen Rontgenabsorptionsfeinstruktur-Phasenfunktionen berechnet. Die gemessenen Daten der ausgedehnten Rontgenabsorptionsfeinstruktur (EXAFS) werden benutzt, um den linear von k abhiingigen Term der Phasenverscbiebung abzuschatzen und i hn mit theoretischen Werten zu vergleichen. Es wird versucht, das Verhalten der Phasenverschie bung eines gegebenen Atompaares bei verschiedenen chemischen Umgebungen und fur unterschiedliche Atompaare in einer gegebenen isoelektronischen Serie von Elementen zu erkliiren.

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Extended X‐ray absorption fine structure (EXAFS) studies of the lanthanides

Cited by 16 publications

References 16 publications

Studies of the kinetics of the vibrational and rotational distribution functions of nitrogen excited by a pulsed discharge

Studies of the kinetics of the vibrational and rotational distribution functions of nitrogen excited by a pulsed discharge

Extended X‐Ray Absorption Fine Structures and Chemical Shifts for the Heavy Rare‐Earth Oxides

Chemical Transferability of Phase Shifts in Extended X‐Ray Absorption Fine Structure

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