A.B. Babaev - Ph.D. (Phys.-Math.), Associate Professor, Institute of Physics, Dagestan Scientific Center, Russian Academy of Sciences (Makhachkala) Е-mail: b_albert78@mail.ru A.K. Murtazaev - Dr.Sc. (Phys.-Math.), Professor, Corresponding Member RAS, Director of Institute of Physics, Dagestan Scientific Center, Russian Academy of Sciences (Makhachkala) E-mail: m_akai2005@mail.ru T.R. Rizvanova - Post-graduate Student, Institute of Physics, Dagestan Scientific Center, Russian Academy of Sciences (Makhachkala) Е-mail: b_albert78@mail.ru