Temperature Dependence of the Width of the Fundamental Lattice-Vibration Absorption Peak in Ionic Crystals. II. Approximate Numerical Results

Ipatova, I. P.; Maradudin, A. A.; Wallis, R. F.

doi:10.1103/physrev.155.882

Cited by 184 publications

(108 citation statements)

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“…Like the frequency shift, the damping generally shows a quadratic temperature dependence in the high temperature limit (Ipatova et al 1967;Gervais & Piriou 1974b).…”

Section: Theoretical Point Of Viewmentioning

confidence: 99%

“…With their assumptions, they obtain a linear temperature dependence of the frequency shift in the high-temperature limit. A quadratic temperature dependence can be obtained by including terms of higher order pertubation theory and/or higher phonon processes as shown by Ipatova et al (1967) and Gervais & Piriou (1974b). By assuming Δω PI j to be sufficiently small, Eq.…”

Section: Theoretical Point Of Viewmentioning

confidence: 99%

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Optical constants of refractory oxides at high temperatures

Zeidler

Posch

Mutschke

2013

A&A

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Context. Many cosmic dust species, among them refractory oxides, form at temperatures higher than 300 K. Nevertheless, most astrophysical studies are based on the room-temperature optical constants of solids, such as corundum and spinel. A more realistic approach is needed for these materials, especially in the context of modeling late-type stars. Aims. We aimed at deriving sets of optical constants of selected, astrophysically relevant oxide dust species with high melting points. Methods. A high-temperature, high-pressure cell and a Fourier-transform spectrometer were used to measure reflectance spectra of polished samples. For corundum (α-Al 2 O 3 ), spinel (MgAl 2 O 4 ), and α-quartz (SiO 2 ), temperature-dependent optical constants were measured from 300 K up to more than 900 K. Small particle spectra were also calculated from these data. Results. All three examined oxides show a significant temperature dependence of their mid-IR bands. For the case of corundum, we find that the 13 μm emission feature -seen in the IR spectra of many AGB stars -can very well be assigned to this mineral species. The best fit of the feature is achieved with oblate corundum grains at (mean) temperatures around 550 K. Spinel remains a viable carrier of the 13 μ feature as well, but only for T < 300 K and nearly spherical grain shapes. Under such circumstances, spinel grains may also account for the 31.8 μm band that is frequently seen in sources of the 13 μm feature and which has not yet been identified with certainty.

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“…Like the frequency shift, the damping generally shows a quadratic temperature dependence in the high temperature limit (Ipatova et al 1967;Gervais & Piriou 1974b).…”

Section: Theoretical Point Of Viewmentioning

confidence: 99%

Section: Theoretical Point Of Viewmentioning

confidence: 99%

Optical constants of refractory oxides at high temperatures

Zeidler

Posch

Mutschke

2013

A&A

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“…44 Note that in the case where the couplings between two particular modes are dominant (in particular due to accidental frequency degeneracy), the problem can be limited to a two-mode system, and is developed below.…”

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confidence: 99%

Effect of pressure and temperature on Raman spectra of solids: anharmonicity

Lucazeau

2003

J Raman Spectroscopy

266

222

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This paper gives a brief review of the effect of temperature and pressure on Raman spectra. Anharmonicity, defined by the cubic, quartic and higher terms in the potential expansion, is shown to be responsible for various properties such as dilatation or for variations of wavenumber and half-width of Raman bands with temperature and pressure, or may be strongly involved in phase transitions. This contribution does not pretend to be an exhaustive review on the subject but aims to introduce some basic concepts in a tutorial way before showing how intricated are these manifestations of anharmonicity. Copyright INTRODUCTIONProperties of materials are dependent on temperature and pressure. All applied research consists in studying the temperature and pressure dependence of their physical properties with a view to preparing the material to exhibit the expected properties in specific conditions of thermal and mechanical stress environment. Basic research consists in relating micro/meso-structural properties with the other physical properties. These relations exist via coupling coefficients which are often defined by a linear relationship. The present review presents the relations which govern the temperature and pressure dependence of the usual spectral parameters such as wavenumber, half-width and intensity of Raman bands. We shall point out the nonlinearity, also defined as anharmonicity, of the corresponding relationships. A tutorial and brief presentation of anharmonic effects in solids can be found in Chapter 8 of Ref. 1. As written by Sherman and Wilkinson, 2,3 in a completely harmonic approximation, where the force constant operating between any two masses is truly a constant and independent of the distance between the masses, the application of pressure would cause no observable frequency shift effects at all. The same statement can be done about the effect of temperature. However, as it becomes evident in the present special issue, this is not verified experimentally.Ł Correspondence to: Guy Lucazeau, LEPMI, (CNRS UMR 5631), Institut National Polytechnique de Grenoble, BP 75, F-38402 St. Martin d'Hères, Cedex, France. E-mail: guy.lucazeau@lepmi.inpg.fr † In memory of Evangelos Anastassakis, who should have been solicited for writing a review paper on such a subject.One of the aims of this paper is to point out that the measurements of temperature-or pressure-induced frequency shifts are measurements of the anharmonicity of the interactions that supply the restoring force constants. Let us point out that because pressure or temperature induces isotropic or anisotropic deformations of molecules and crystals, the pressure or stress-induced and the temperatureinduced frequency shifts  / are mainly determined by the associated deformation V/V. It is thus important to analyze the effects of temperature and pressure together. The origin of the deformation induced by these two external parameters is different. Pressure affects the equilibrium spacings between nuclei, distorts the electron clouds and through them...

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“…Выделяют три процесса, дающие вклад в собственную энергию, согласно основному порядку теории возмущений [27]: а) двухфононные процессы, б) тепловые флуктуации, в) тепловое расширение, при этом все три процесса вкладывают в смещение линии, но только процесс а) вкладывает в ширину линии [27,28].…”

Section: метод расчетаunclassified

Фононные спектры, однофононные и двухфононные плотности состояний UO-=SUB=-2-=/SUB=- и PuO-=SUB=-2-=/SUB=-

Поплавной¹,

Федорова²,

Федоров³

2017

Физика Твердого Тела

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Вычислены колебательные спектры UO2 и PuO2 в феноменологической модели жестких ионов, однофононные и взвешенные тепловыми числами заполнения двухфононные плотности частот. За счет различия масс металла и кислорода на порядок величины акустические ветви обусловлены в основном колебаниями металла, оптические --- кислорода. Это позволяет представить спектры в двух зонах Бриллюэна (ЗБ) --- кристалла и подрешетки кислорода, при этом число оптических ветвей уменьшается вдвое. Двухфононные плотности состояний представляют собой два широких структурированных пика. Температурные зависимости верхнего пика показывают тепловое уширение фононных линий L01 и L02 в верхней части оптических ветвей. Нижний пик отвечает за тепловое уширение двух самых нижних оптических (T02, T01) и акустических (LA, TA) ветвей. Работа выполнена при поддержке госзадания N 3.1235.2014К. DOI: 10.21883/FTT.2017.04.44278.291

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Temperature Dependence of the Width of the Fundamental Lattice-Vibration Absorption Peak in Ionic Crystals. II. Approximate Numerical Results

Cited by 184 publications

References 13 publications

Optical constants of refractory oxides at high temperatures

Optical constants of refractory oxides at high temperatures

Effect of pressure and temperature on Raman spectra of solids: anharmonicity

Фононные спектры, однофононные и двухфононные плотности состояний UO-=SUB=-2-=/SUB=- и PuO-=SUB=-2-=/SUB=-

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