Core thresholds in alkali metals

Slusky, S. E. G.; Schnatterly, S. E.; Gibbons, P. C.

doi:10.1103/physrevb.20.379

Cited by 21 publications

(5 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is true that the experiment of Ritsko et al for Li and that of Slusky et al (1976) for Mg tested negatively the prediction of Doniach et al (1971) that an edge peak would be observed, even in the K excitation spectrum, if the momentum transfer q of an incident electron were large enough to relax the selection rule. But Slusky et al (1979) showed later that in the case of Na, K, and Mg, the q dependence of the loss spectrum was not contradictory to the MND theory. Theoretically, shows that the observed spectra, including those of Li, could be understood naturally within the context of the MND model when one took account of instrumental resolution and the deviation of the spectral shape due to the generalized power law.…”

Section: )mentioning

confidence: 95%

Theory of the soft-x-ray edge problem in simple metals: historical survey and recent developments

1990

View full text Add to dashboard Cite

show abstract

Section: )mentioning

confidence: 95%

Theory of the soft-x-ray edge problem in simple metals: historical survey and recent developments

1990

View full text Add to dashboard Cite

show abstract

“…In this way we are able to improve on the analysis of Ref. 15. We tested for the existence of CDW's in the samples r by including the convolution function UiE)^^ -IE I) " 1/2 6(/x -IE I) in the model of the threshold data.…”

Section: -E 3 ) 2 +(Y/2) 2 E(e 3 )Er a (L+me 3 )mentioning

confidence: 99%

“…The energy required to remove an electron from a given core level should be affected by the presence of a CDW identically in all three cases. We have reanalyzed IES data at the Na £2,3 and K M2,3 core thresholds, 15 and Na £2,3 SXE data of other workers. 1617 In contrast to BBLP we find that phonon coupling is important for the understanding of the shapes of these edges and that the data do not call for the presence of a CDW.…”

mentioning

confidence: 99%

“…After multiplying by the MND power law peaking at the edge, we broaden the model with the following three convolution functions to describe established effects on the spectra: (l) a Lorentzian due to the finite lifetime of the core hole, (2) a Gaussian for instrumental and phonon broadening in absorption, and (3) the function which provides the temperature-dependent Fermi-Dirac broadening. 15 To include CDW broadening we also convolute the model with a fourth function. The fitting model for IES thresholds without CDW broadening is shown below: …”

mentioning

confidence: 99%

See 1 more Smart Citation

Core Thresholds and Charge-Density Waves in Alkali Metals

Brühwiler

Schnatterly

1988

Phys. Rev. Lett.

Self Cite

View full text Add to dashboard Cite

We have determined experimental upper limits on any broadening which could be due to a chargedensity wave in Na and K metal soft-x-ray absorption and emission spectra. The upper limit for absorption in Na is a factor of 4 below the expected theoretical value. These results contradict expectations based on the present theory of charge-density waves in alkali metals. PACS numbers: 78.70.Dm, 71.45.Lr, 78.70.EnDuring the past two years considerable attention has been given to the search for charge-density waves (CDW's) in alkali metals, 1 " 8 with ambiguous results. Diffraction measurements have been carried out on K with both positive 1 and negative 2 results. In addition the results of photoemission measurements 3 on Na have been interpereted both ways. 3 " 6 Diffraction would seem to provide the best test for the existence of a periodic structure; Overhauser has pointed out, 7 ' 9 however, that domains of Q, the CDW wave vector, could be distributed randomly or preferentially, depending upon poorly understood factors of sample preparation. It is possible therefore to challenge 7 negative diffraction results 2 as inconclusive.Quite recently Bishop et al % (hereafter refered to as BBLP) calculated the soft-x-ray emission (SXE) spectra at the Na 1,2,3 and Li K edges, assuming the presence of a CDW in its ground state. They assert that CDW coupling enables a self-consistent picture of these threshold shapes within the Mahan-Nozieres-de Dominicis (MND) framework, 10,11 and that the more generally accepted phonon-coupling theories 12 " 14 do not. The strength of using a core spectroscopy to search for CDW's lies in the fact that a CDW would be expected to cause position-dependent core-level energy shifts which are independent of the direction of Q. The spectra are not susceptible to domain-control difficulties postulated by Overhauser 9 for diffraction, since CDW phase coherence over large distances is not required. Bulk core spec-

show abstract

“…For instance, the L II,III edges of Na, [1][2][3][4][5][6][7][8][9][10][11] Mg, 1,4,6,7,[10][11][12][13][14][15][16][17][18][19][20] and Al, 1,4,6,7,11,12,[14][15][16][17]19,[21][22][23] as well as the M II,III edge of K, [24][25][26] are sharp but slightly peaked while the K edges of Li, 1,3,6,7,13,14,19,20,23,[27]...…”

Section: Introductionmentioning

confidence: 99%

X-ray line shapes of metals: Exact solutions of a final-state interaction model

Swarts¹,

Dow²

2005

Phys. Rev. B

View full text Add to dashboard Cite

By means of model calculations for an independent-electron metal, we obtain exact line shapes for the photon absorption, emission, and photoemission spectra of core states, including electronic relaxation. In all cases we find an x-ray edge anomaly. For the absorption and emission spectra this anomaly is superposed on a continuum resembling Elliott exciton theory. We display how the spectra evolve from the exciton limit to the free-electron limit as the final-state interaction strength is decreased or the Fermi energy increased. We compare the spectra obtained for different final-state interactions and find that different types of interactions produce different spectral shapes. Away from threshold the absorption and emission profiles show an enhancement of the free-electron result, as predicted by the screened-exciton theory. Our results offer potential explanations for ͑i͒ incompatibilities between threshold exponents and exponents extracted from other data, ͑ii͒ the occurrence of nearly symmetric x-ray photoemission lines, and ͑iii͒ the lack of mirror symmetry of absorption and emission edges.

show abstract

Core thresholds in alkali metals

Cited by 21 publications

References 36 publications

Theory of the soft-x-ray edge problem in simple metals: historical survey and recent developments

Theory of the soft-x-ray edge problem in simple metals: historical survey and recent developments

Core Thresholds and Charge-Density Waves in Alkali Metals

X-ray line shapes of metals: Exact solutions of a final-state interaction model

Contact Info

Product

Resources

About