Estimation of the Gruneisen parameter and an explicit measure of anharmonicity of dodecaborides

Науковий вісник Львівського національного університету ветеринарної медицини та біотехнологій імені С.З. Ґжицького. Серія: Харчові технології

D. Vadets¹  O. Garashchenko¹  Y. Fedyshyn²  T. Fedyshyn²  O. Romanov³ 

[1] National University of Water Economy and Nature Management, Rivne, Ukraine;Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnologies Lviv, Ukraine;Zhytomyr State Technological University, Zhytomyr, Ukraine;

关键词: gruneisen constant, debye characteristic temperature, x-ray characteristic temperature, lindemann formu-la, gruneisen formula, anharmonicity of oscillations of crystal particles, dodecaborides;   

DOI  :  10.32718/nvlvet9001

来源: DOAJ

【 摘 要 】

In previous works on the ratio   (θД – the characteristic temperature of Debye, was calculated according to the Lindemann formula; V – molar volume of hypothetical lattice atoms; γ is the Gruneisen parameter) for the group of dodecaborides (TbB12, DyB12, HoB12, ErB12, TuB12, LaB12, UB12) the average value of γ = 1.3 was determined. However, due to the ambiguity of the coefficient of proportionality in the Lindemann formula by definition θD, the authors selected an independent high-temperature X-ray method for determining the dependence θr (T). Taking into account the immutability of the structure and type of interatomic connection in the temperature interval of the search (293–973 K), the authors evaluated the value and temperature dependence of γ (T) of each dodecaboride separately. The results of the search showed that the value of γ for each given dodecaboride is different, but practically independent from temperature. For some dodecaborides, the parameter γ is about 2–3 units, and for others it is overestimated. The values of γ made it possible to estimate the magnitude of the implicit γβ and the explicit  parts of the universal measure of anharmonicity of dodecaborides , where β – real coefficient of volumetric expansion of the crystalline lattice. Because    (n – dimensionless coefficient of proportionality), then the temperature change n(T) is also determined.

【 授权许可】

Unknown