Труды сотрудников института физики

/ E. M. Aver'yanov // JETP Letters. - 2008. - Vol. 87, Is. 5. - P. 258-261 ; JETP Letters. - 2008. - Vol. 87, Is. 5. - P. 258-261, DOI 10.1134/S002136400805007X. - Cited References: 14 . - ISSN 0021-3640. - Вариант SopusРУБ Physics, Multidisciplinary

Аннотация: The nonlinear relation between the mean effective polarizability (gamma) over bar of molecules and the local-field anisotropy in uniaxial liquid crystals is demonstrated. Stringent constraints on (gamma) over bar from below, indicative of the dependence of on the liquid-crystal state and the change of the "(gamma) over bar = const" paradigm, are established. The theoretical results are confirmed by experiments with nematic liquid crystals having high and low birefringences.

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation
Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation

Доп.точки доступа:
Аверьянов, Евгений Михайлович

/ E. M. Aver'yanov // J. Exp. Theor. Phys. - 2009. - Vol. 108, Is. 1. - P. 176-186, DOI 10.1134/S106377610901021X. - Cited References: 35 . - ISSN 1063-7761РУБ Physics, Multidisciplinary

Аннотация: The problems on the relation of the mean effective molecular polarizability (gamma) over bar to the long-range orientational order of molecules (the optical anisotropy of the medium) in uniaxial and biaxial liquid crystals, the local anisotropy on mesoscopic scales, and the anisotropy of the Lorentz tensor L and the local-field tensor f are formulated and solved. It is demonstrated that the presence of the long-range orientational order of molecules in liquid crystals imposes limitations from below on the molecular polarizability (gamma) over bar, which differs for uniaxial and biaxial liquid crystals. The relation between the local anisotropy and the molecular polarizability (gamma) over bar is investigated for calamitic and discotic uniaxial liquid crystals consisting of lath- and disk-shaped molecules. These liquid crystals with identical macroscopic symmetry differ in the local anisotropy and the relationships between the components L(parallel to) L(perpendicular to,) f(parallel to) > f(perpendicular to) (discotic) for an electric field oriented parallel and perpendicular to the director. The limitations from below and above on the molecular polarizability (gamma) over bar due to the anisotropy of the tensors L and f are established for liquid crystals of both types. These limitations indicate that the molecular polarizability (gamma) over bar depends on the phase state and the temperature. The factors responsible for the nonphysical consequences of the local-field models based on the approximation (gamma) over bar = const are revealed. The theoretical inferences are confirmed by the experimental data for a number of calamitic nematic liquid crystals with different values of birefringence and the discotic liquid crystal Col(ho).

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation

Доп.точки доступа:
Аверьянов, Евгений Михайлович

/ A. P. Gavrilyuk, S. V. Karpov // Appl. Phys. B-Lasers Opt. - 2009. - Vol. 97, Is. 1. - P163-173, DOI 10.1007/s00340-009-3592-y. - Cited Reference Count: 43. - Гранты: Authors are thankful to Prof. V. A. Markel ( University of Pennsylvania) for computation of multipole polarizability of silver nanoparticle bispheres, for the attention to this paper, fruitful discussions and great support. This research was supported by grants: 27.1 of the Presidium of RAS, 9.1 DPS RAS, 5 SB RAS, 3818.2008.3 and 6612.2006.3 of the President of RF ( SS RAS), DSP 2.1.1.1814, 05- 03- 32642 RFBR. - Финансирующая организация: [27.1 of the Presidium of RAS]; [9.1 DPS RAS]; [5 SB RAS]; [3818.2008.3]; [6612.2006.3] . - SEP. - ISSN 0946-2171
Аннотация: Optical nonlinearities in aggregates of nanoparticles formed in silver hydrosols (SHs) are studied under pico- and nanosecond pulsed laser excitation. The dependence of the nonlinear refractive index n (2) on the degree of hydrosol aggregation is studied experimentally at the wavelength lambda=1.064 mu m. It is found that n (2) changes sign when the degree of hydrosol aggregation is increased. Various physical effects occurring in resonant domains of the aggregates are analyzed using a simple physical model of two bound silver nanoparticles. The theory takes into account thermal, elastic, electrostatic, and light-induced effects. Experimental results are discussed in the context of this theory.

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
Russian Acad Sci, Inst Computat Modeling, Krasnoyarsk 660036, Russia
Siberian Fed Univ, Krasnoyarsk 660028, Russia

Доп.точки доступа:
Gavrilyuk, A. P.; Гаврилюк, Анатолий Петрович; Karpov, S. V.; Карпов, Сергей Васильевич