# Dresden 2006 – wissenschaftliches Programm

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# DY: Dynamik und Statistische Physik

## DY 40: Critical Phenomena and Phase Transitions I

### DY 40.5: Vortrag

### Donnerstag, 30. März 2006, 10:45–11:00, H\"UL 186

**Neutron optics of confined liquids near the critical point** — •Alexander Chalyi^{1}, Leonid Bulavin^{2}, and Kyrylo Chalyy^{3} — ^{1}Department of Physics, National Medical University, 13, Shevchenko Blvd., 01601 Kiev, Ukraine — ^{2}Department of Molecular Physics, Kiev Taras Shevchenko National University, 6, Acad. Glushkov Boulevard, 03022 Kiev, Ukraine — ^{3}Department of Medical Informatics, Kiev Medical Academy, 9, Dorogozhytska Str., 04112 Kiev, Ukraine

The neutron optics methods are applied to theoretical studies of the critical properties of confined liquids. In frame of this approach, analytical calculations are carried out for the density profile together with the neutron refractive index profile for non-uniform liquids at restricted geometry. Special attention is paid to gravity effects on properties of liquid systems. New results are obtained for the shifts of the critical temperature on the phase coexistence curve and positions of inflection points on the critical isotherm in confined liquids. The problem of propagation of the neutron beam in a non-uniform liquid at restricted geometry is solved. Special attention is paid to peculiarities of the refraction of neutrons due to the spatial limitation of a liquid system (namely, the corresponding formula for refractive angle of neutrons in finite-size individual and binary liquids are obtained and analyzed). The form of refractive index ellipsoid is studied and possible experimental consequences of neutron refraction in confined liquids are discussed. Dependence of the neutron propagation and elastic scattering in finite-size liquids on temperature (field) variables and geometrical factors is studied with confinement effects taken into account.