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1

Computational Method of X-Ray Harmonic Elimination in EXAFS Treating

100%

Ovsjannikov P. M.

Acta Physica Polonica A

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1994

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vol. 86

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issue 5

749-752

EN

The computational method of EXAFS amplitude correction by harmonics elimination and intensity leakage assessment has been worked out. In conventional absorption measurements, the major sources of errors are the transition of harmonics by the monochromator and inevitable leakage of radiation around and (or) through the sample. In this paper we present the method of the effective corrections being based on the measurements of the intensity of X-ray radiation passed through calibrated metal foils both without and together with investigated samples. As the advantage of the method one may emphasise the fact that it does not require any additional data for the investigated samples such as chemical composition, density, table absorption coefficients.

2

EXAFS Studies of Zn_{1-x}Mn_{x}S Ternary Compounds

100%

Zimnal-Starnawska M., Łażewski J., Kisiel A., Boscherini F., Pascareli S., Giriat W.

Acta Physica Polonica A

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1994

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vol. 86

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issue 5

763-766

EN

We performed extended X-ray absorption fine structure (EXAFS) measurements of Zn_{1-x}Mn_{x}S solid solution for various concentrations x in the range of 0 ≤ x ≤ 0.4. Data were collected on Zn and Mn K-edges with the use of synchrotron radiation from the ADONE storage ring in Frascati utilizing the Si(111) channel-cut monochromator. Applying the usual procedure of data reduction described elsewhere, we found well-defined different nearest-neighbor Zn-S and Mn-S distances, according to the previous results, almost independent on x. For Mn-S distances in the range of 0.1 ≤ x ≤ 1.0 we found, within the limit of experimental error, a constant value equal to 2.430±0.008 Å. For Zn-S distances for concentration changing from x = 0.0 to x = 0.4 we observed a weak, linear increase from 2.343±0.008 Å to 2.354 ± 0.008 Å, respectively.

3

Extended X-Ray Absorption Fine Structure Studies of Co Doped ZnS and ZnSe Alloys

80%

Ławniczak-Jabłońska K., Gołacki Z.

Acta Physica Polonica A

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1994

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vol. 86

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issue 5

727-735

EN

X-ray absorption experiments were performed at the Kedge of Co and Zn in Zn_{1-x}Co_{x}S and Zn_{1-n}Co_{x}Se compounds with x = 0.25, 0.16, 0.10, 0.05, 0.00 in the sulphides samples and x = 0.07, 0.02, 0.00 in the selenide ones. Analysis of the extended X-ray absorption fine structure oscillations using phase and amplitudes either from McKale code or from standard samples, gave the distance, number of atoms and the Debye-Waller factors for nearest neighbours. We found that the cation-anion distances Zn-S(Se) or Co-S(Se) are systematically shorter in ZnS than in ZnSe matrix, the Zn-anion distance is always larger than the Co-anion one without any significant Co content dependence. This allowed us to estimate the covalent radius of Co in the studied matrices to be 0.025 Å smaller than the Zn covalent radius and stated that covalent radius of Co is independent of the type of surrounding atoms. In addition the Debye-Waller factors indicated a better ordering in ternary compounds than in the binary standard ones in agreement with rocking curve measurements.

Refine search results

3 Acta Physica Polonica A

3 1994

1 Boscherini F.

1 Giriat W.

1 Gołacki Z.

1 Kisiel A.

1 Ovsjannikov P. M.

1 Pascareli S.

1 Zimnal-Starnawska M.

1 Ławniczak-Jabłońska K.

1 Łażewski J.

Computational Method of X-Ray Harmonic Elimination in EXAFS Treating

EXAFS Studies of Zn_{1-x}Mn_{x}S Ternary Compounds

Extended X-Ray Absorption Fine Structure Studies of Co Doped ZnS and ZnSe Alloys