May 10, 1951 is birth date of Yuriy Izmaylov, Doctor of Sciences (Chemistry), Professor. He died tragically on June 14, 1998.

In connection with the development and the increasing availability of computer modeling of materials based on the first principles, and the emergence of conflicting data about the results of their use there are attempts to justify the use of computing technology on the example of the promising applications of systems – carbon nanotubes. Issues related to the selection of geometric parameters of the model (diameter, length, tube symmetry), ways to optimize its starting configuration, the selection of approximations required to describe electronic structure in the framework of functional electron density theory are discussed. Arguments are supported by the reference to the experience gained by the authors earlier, as well as a variety of calculations carried out specifically in the preparation of this paper.

First principle molecular dynamics method is used to simulate the structure and dynamic properties of carbon nanotubes with lithium atoms in a cavity at temperature range of 100–700 K. It is shown that basic patterns in the structure of these complexes, revealed at T = 0 K, are kept at all considered temperatures. The character of the motion of interstitial atoms depending on their concentration and temperature is studied. It is predicted that movement of atoms at low lithium concentrations becomes infinite at temperatures greater than 300 K. On the contrary, at concentrations above the threshold of clustering, the movement of clusters of lithium is infinite at the lowest of considered temperatures.

The paper presents the results of quantum-mechanical calculations of the mechanical properties of chiral carbon nanotubes. We assess the conditions under which the boundary effects can be neglected in the simulation. Tensile strength, Young's modulus and shear energy for optimized nanotubes geometry were identified. The ranges of strains of nanotubes in which they have not experienced fracture. were defined.

Созыкин Сергей Анатольевич – аспирант, кафедра общей и теоретической физики, физический факультет, Южно-Уральский государственный университет. E-mail: sergey.sozykin@gmail.com Бескачко Валерий Петрович – доктор физико-математических наук, профессор, кафедра общей и теоретической физики, физический факультет, Южно-Уральский государственный университет. Sozykin Sergey Anatolevich is Post-graduate student, General and Theoretical Physics Department, South Ural State University. E-mail: sergey.sozykin@gmail.com. Beskachko Valeriy Petrovich is Dr. Sc. (Physics and Mathematics), Professor, General and Theoretical Physics Department, South Ural State University.