Thermal vacancy effects on the thermodynamic properties and stability of fullerites

We study the influence of thermal vacancies on equilibrium thermodynamic properties of the high-temperature phase of fullerites taking into account the strong anharmonicity of the lattice vibrations. Treating a crystal with point defects as a quasi-multicomponent system and using the correlative method of the unsymmetrized self-consistent field and the Girifalco interaction potential for the molecular subsystem, we have obtained the vacancy formation parameters for the C60 fullerite. We also take into account the divacancies. The influence of the lattice defects on the specific heats of fullerites is negligible, since a dominant contribution to them is given by intramolecular degrees of freedom. We have calculated the contributions of vacancies to various thermodynamic properties, the volume thermal expansion coefficient, the isothermal bulk modulus, and the components of the isothermal elastic tensor, depending on the temperature and pressure. Near the estimated triple point, these contributions run to more than 10% and increase still further at a metastable region. We also discuss the influence of defects on the thermodynamic stability of fullerites. © 2005 American Chemical Society.

Авторы
Редакторы
-
Издательство
-
Номер выпуска
30
Язык
Английский
Страницы
14627-14631
Статус
Опубликовано
Подразделение
-
Номер
-
Том
109
Год
2005
Организации
  • 1 Department of Theoretical Physics, Peoples' Friendship University, 117198 Moscow, Russian Federation
Ключевые слова
Crystal defects; Entropy; Lattice constants; Molecular vibrations; Phase equilibria; Tensors; Thermodynamic properties; Elastic tensor; Fullerites; Quasi-multicomponent systems; Vacancy effects; Fullerenes
Дата создания
19.10.2018
Дата изменения
19.10.2018
Постоянная ссылка
https://repository.rudn.ru/ru/records/article/record/3465/