Small-angle neutron scattering from heavy water in the vicinity of the critical point
| Autor: | Marie-Claire Bellissent-Funel, P. Calmettes, G. Romet-Lemonne, Marco Bonetti |
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| Rok vydání: | 2000 |
| Předmět: |
Heavy water
Correlation function (statistical mechanics) chemistry.chemical_compound Amplitude Condensed matter physics Chemistry Critical point (thermodynamics) Critical phenomena Neutron diffraction General Physics and Astronomy Physical and Theoretical Chemistry Neutron scattering Small-angle neutron scattering |
| Zdroj: | The Journal of Chemical Physics. 112:268-274 |
| ISSN: | 1089-7690 0021-9606 |
| Popis: | Small-angle neutron scattering spectra from supercritical heavy water were recorded along a near-critical isochore at temperatures between (Tc,exp+1.63 K) and (Tc,exp+22.02 K), Tc,exp being the experimental critical temperature. At low values of the wave number transfer q, the scattered intensity shows a pronounced increase due to the divergence of density fluctuations at the critical point. In the studied q range, from 0.07 to 0.36 A−1, all the spectra can be accurately described by the Fisher–Langer correlation function provided that a multiplicative additional term describing short-range correlations between water molecules is taken into account. The value found for the amplitude of the critical correlation length is ξ0=(1.36±0.06) A, in fair agreement with the value predicted by the two-scale hypothesis. |
| Databáze: | OpenAIRE |
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