Angular variations in core-level XPS peak intensity ratios from single-crystal solids

Evans, Stephen D.; Raftery, E.; Thomas, John Meurig

doi:10.1016/0039-6028(79)90593-4

Cited by 33 publications

(14 citation statements)

References 7 publications

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“…The increased repeat distance relative to the micas is not important because most of the XPD structure is generated by elastic scattering from atoms quite close to the emitter. The Si/Mg patterns from a vermiculite (do01 also --14 ,~) without interlayer Mg are thus virtually identical to those of other micas (Evans et al 1979a(Evans et al , 1979b. However, if both chlorites were of Bailey's Type I, with the octahedral slant in the interlayer parallel to that in the 2:1 layer, the nearestneighbor directions surrounding the octahedral cations would be the same.…”

Section: Interpretation Of the Photoelectron Diffraction Patternsmentioning

confidence: 68%

“…These apparent compositions were averaged over the whole angular range. Compositions obtained in this way are effectively angleintegrated, and are not affected by the diffraction modulation evident in all such data from single crystals (Evans et al 1979b). …”

Section: Experimental and Data Processingmentioning

confidence: 94%

“…In these cases, therefore, it has been reasonable to infer bulk characterization from that at the surface. However, for samples of phlogopite, vermiculite and lithium biotite, cleavage was found to occur most readily in regions of high A1 content (Evans et al 1979a(Evans et al , 1979b) while a lepidolite has been shown to cleave preferentially in manganese-enriched regions (Evans and Raftery 1982).…”

Section: Introductionmentioning

confidence: 93%

“…If the A1 and Mg were distributed similarly between the various octahedral sites, the Si/A1 patterns would merely be weaker copies of those for Si/Mg, because some of the A1 occupies tetrahedral sites equivalent to those of Si and has the same angular dependence. The percentage by which the anisotropy is reduced would directly indicate the percentage of the A1 in tetrahedral sites (Evans et al 1979b). Since the Si/Mg and Si/A1 patterns have quite similar profiles between approximately 10 ~ and 50 ~ despite the Mg and A1 having differing distributions between the 2:1 layer sites and the brucitic-layer sites, this should still represent a reasonable approximation.…”

Section: Estimation Of the Percentage Of Tetrahedral Alu-mentioning

confidence: 99%

“…The Si and Mg analyses were derived from both the 2s and the 2p peaks, A1 from A12s only, using the procedures described by Evans et al (1978) and Evans et al (1979b). The symbol • denotes experimental rotation axes parallel and antiparallel to the crystallographic direction specified.…”

Section: Experimental and Data Processingmentioning

confidence: 99%

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Angle-Resolved X-Ray Photoelectron Studies of Cleavage in Chlorites

Evans

Hiorns

1996

Clays and clay miner.

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Abstract--The cleavage of two single-crystal chlorites (a clinochlore and a penninite) has been studied using angle-resolved X-ray photoelectron spectroscopy (XPS). Both minerals cleaved in regions not typical of the bulk; the composition of the clinochlore was found to be especially non-uniform. The brncitic interlayer divided evenly between the pair of new surfaces exposed for two cleaves in the clinochlore, but was partitioned unequally in two cleaves in the penninite. The differences in apparent composition between the complementary pairs of surfaces are interpreted to show a marked preference of octahedral A1 for the brucitic layer, in agreement with X-ray bulk structure refinements. For both chlorites, the layer charge was reduced in regions of easy cleavage, which also had a higher proportion of Si and less tetrahedral A1 than the bulk chlorite. The percentages of tetrahedral aluminium deduced from the XPS surface analyses agreed satisfactorily with the percentages independently determined by consideration of the magnitude of anisotropy in the X-ray photoelectron diffraction (XPD) patterns. The XPD patterns from the clinochlore for rotation about axes parallel and antiparallel to the crystallographic a-axis were identical, showing that tetrahedral ordering was absent.

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Section: Interpretation Of the Photoelectron Diffraction Patternsmentioning

confidence: 68%

Section: Experimental and Data Processingmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 93%

Section: Estimation Of the Percentage Of Tetrahedral Alu-mentioning

confidence: 99%

Section: Experimental and Data Processingmentioning

confidence: 99%

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Angle-Resolved X-Ray Photoelectron Studies of Cleavage in Chlorites

Evans

Hiorns

1996

Clays and clay miner.

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The quantitative analysis of surfaces by XPS: A review

Seah

1980

Surface & Interface Analysis

417

146

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A general framework is presented for the quantitative analysis of surfaces by X-ray photoelectron spectroscopy (XPS or ESCA). The approach starts by considering analysis using reference data recorded on the same instrument and under identical conditions as the analysed sample. Matrix factors are evaluated and the quantification for adsorbed layers and sputter profiles discussed. More popularly reference data are not recorded each time but are taken from the published literature. In this case the angular anisotropy term and analyser transmission functions need to be known. These are discussed and the analyser transfer functions of commercial spectrometers are presented in detail. Nine published reference data sets are assessed to test their correlation with the theoretical predictions. Three sets are found to give moderate agreement but agree more closely with each other in their divergence from the theory for particular elements. This divergence enables a peak intensity factor to be defined which quantifies the intensity lost from a peak due to shake-up events, etc. With this factor and the analyser transfer functions quantification can be made to an accuracy of 10% in all instruments from a single reference data set.

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Chemical and structural characterization of epitaxial compound semiconductor layers using X‐ray photoelectron diffraction

Evans

Scott

1981

Surface & Interface Analysis

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The application of angle-resolved X-ray photoelectron spectroscopy (X-ray photoelectron diffraction) to characterize thin layers of compound semiconductors grown on single crystal substrates is described. in studies of ZnSe grown on (100) GaAs, confirmation of the epitaxial character of the growth, together with a quantitative estimate (f5%) of the stoichiometry of the ZnSe layer, were achieved by means of a single experiment. The techniques described are equally applicable to very thin layers (

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Angular variations in core-level XPS peak intensity ratios from single-crystal solids

Cited by 33 publications

References 7 publications

Angle-Resolved X-Ray Photoelectron Studies of Cleavage in Chlorites

Angle-Resolved X-Ray Photoelectron Studies of Cleavage in Chlorites

The quantitative analysis of surfaces by XPS: A review

Chemical and structural characterization of epitaxial compound semiconductor layers using X‐ray photoelectron diffraction

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