Аннотации:
Представлены результаты обоснования выбора формы потенциала
межмолекулярного взаимодействий, адекватно описывающего структуру
взаимодействий в молекулярном кристалле нитросоединения. Показано,
что энергия электростатического взаимодействия может составлять до
25 % от теплоты сублимации молекулярных кристаллов нитросоединений.
Данное заключение позволило определить форму потенциала невалентных
взаимодействий для построения двучленного уравнения состояния молекулярных кристаллов. Были получены замыкающие соотношения, определяющие параметры потенциала невалентных взаимодействий и упругую
составляющую уравнений состояния. The paper analyzers the diagram of atom-atom potentials as exemplified by calculation of energy of
the molecular crystal lattice of nitro compounds. The performed in the paper calculations of energy of
the crystal lattice of a number of nitro compounds have shown that the calculation data coincide with the
experiment only when an electrostatic interaction between molecules is taken into account in the diagram
of atom-atom potentials. The obtained results allowed us to create a potential for description of an
elastic component of the internal energy and pressure in the two-term state equation of the molecular
crystal. The accounting of electrostatic energy has lead to the fact the in the Buckingham potential when
describing the attraction energy an unknown parameter, i.e. a power coefficient for specific volume of
the crystal, appears. On the whole, there are four parameters in the potential for description of the elastic
component of the internal energy and pressure. These parameters are determined from experimental
data. The analysis of experimental data on thermodynamic measurements has shown that the most adequate
description of the elastic component of the internal energy and pressure in the two-term state equation
of molecular crystals can be received only when the potential of intermolecular interactions closes
on the isothermal compressibility or sound speed at the temperature of the crystal tending to zero. The
consecutive passage to the limit in terms of the isothermal sound velocity for the crystal temperature,
tending to zero, allowed us to get a rather simple potential for description of the elastic component of the
internal energy and pressure, expression of which includes an explicitly isothermal sound speed. This
approach enables us to reduce the number of unknown parameters to two, which are specified according
to experimental shock adiabats
Описание:
Ю.М. Ковалев,
Южно-Уральский государственный университет, г. Челябинск, Российская Федерация
E-mail: kovalevym@susu.ru. Yu.M. Kovalev
South Ural State University, Chelyabinsk, Russian Federation
E-mail: kovalevym@susu.ru