Materials physics and mechanics

RAR RUS 1-10 Peter the Great St. Petersburg Polytechnic University Sanin

St.Petersburg, Russia

Bagmanov Quantum Oscillator under External Impulse Force In this contribution dynamics of quantum oscillator under external impulse force is investigated. The oscillator with symmetric polynomial potential in the well of impenetrable walls is considered. The potential consists of quadratic and cubic terms; the cubic term depends on modulus of coordinate. Influence of walls and anharmonicity on vibrations is discussed. Properties and peculiarities of resonances have been studied in context of non-stationary Schrödinger's equation at specified initial conditions. Solutions for the probability density, expectation coordinate as function of time; Fourier's spectra were analyzed in detail. Quantum Oscillator External Impulse Force https://mpm.spbstu.ru/article/2010.12.1/ MPM_9_1_P01.pdf

RAR RUS 11-19 Peter the Great St. Petersburg Polytechnic University Melker A.I.

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Krupina

St.Petersburg, Russia

Hidden Symmetry or why Ciclic Molecules Have so Strange Forms In this contribution we report on a study of conformation transitions in a cyclohexane in the temperature range from –100° to 1200°С. The bond charge molecular dynamics was used. To explain the results obtained, we have developed a method with the help of which the theory of electron pairs repulsion can be enlarged and be applied to cyclic molecules. The approach created reveals a hidden symmetry of spatial electronic structure which, in general, does not coincide with the symmetry of a visible atomic structure. However this spatial electronic structure presets an atomic structure and explains why a cyclohexane molecule has so unusual conformations as a boat and a chair. Ciclic Molecules Hidden Symmetry https://mpm.spbstu.ru/article/2010.12.2/ MPM_9_1_P02.pdf

RAR RUS 20-25 Peter the Great St. Petersburg Polytechnic University Krupina

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Melker A.I.

St.Petersburg, Russia

Unified Approach to Vibrations and Rotations of Molecules and Macromolecules In this contribution we have briefly analyzed the approach lying at the basis of semi-empirical calculation of the potential barrier for molecule internal rotations. In opposite to it, we have suggested the way how to find this barrier on purely theoretical grounds. For this purpose, we have used the bond-charge model with clamped charges, and in this contribution restricted ourselves by the simplest case of such molecules as ethane. It was found that this approach leads to theoretical results which are in a good agreement with experimental data. It means that the electronic theory of molecule vibrations developed earlier has a large degree of generality and can be used to study not only vibrations but also rotations of molecules and macromolecules on the basis of one and the same approach, excluding a lot of empirical parameters which are often do not clarify a subject but immerse it into darkness. Molecules Macromolecules Vibrations Rotations https://mpm.spbstu.ru/article/2010.12.3/ MPM_9_1_P03.pdf

RAR RUS 26-34 Belarusian State University of Informatics and Radioelectronics Nelayev

Minsk, Belarus

Belarusian State University of Informatics and Radioelectronics Mironchik

Minsk, Belarus

Magnetism of Graphene with Vacancy Clusters Graphene, a plane object composed of carbon atoms, is a perspective material for nanoelectronics and spintronics because of its unique electron and magnetic properties. It was found that graphene reveals spin polarization effect, i.e. its magnetic features increase when crystal defects (vacancies and clusters of vacancies) are introduced. Systematic analysis is performed by ab initio simulation with the use of VASP program complex in order to state spin polarization dependence of graphene on the number vacancies in a cluster and on a cluster configuration. Graphene Vacancy Clusters Magnetism https://mpm.spbstu.ru/article/2010.12.4/ MPM_9_1_P04.pdf

RAR RUS 35-41 Institute of Theoretical Physics and Astronomy of Vilnius University Tamuliene

Vilnius, Lithuania

Vilnius Pedagogical University Vaišnoras

Vilnius, Lithuania

The Institute of Photonic Sciences Badenes

Castelldefels, Spain

Vilnius University Balevičius

Vilnius, Lithuania

Point of View on Magnetic Properties of Con (n=6,8,10,12) Based on Quantum Chemistry Investigations In this paper we present quantum chemical investigations on magnetic properties of several Co nanoparticles. Results of magnetizability, g-tenzor, and the nature of bond and charge distribution in the particles are also presented. The results obtained allow us to propose reasons due to which magnetic properties of small particles are different and speculate what affected them Quantum Chemistry Magnetic Properties Co nanoparticles https://mpm.spbstu.ru/article/2010.12.5/ MPM_9_1_P05.pdf

RAR RUS 42-52 Vilnius University Juršėnas

Vilnius, Lithuania

Vilnius University Merkelis

Vilnius, Lithuania

Application of Symbolic Programming for Atomic Many-Body Theory In the present paper a symbolic programming method for generation of the expansion–terms expressions of atomic stationary perturbation theory is presented by using Mathematica system. For this purpose the package named as NCoperators was developed. Producing the PT terms, this package accommodates the features of the RayleighSchrödinger perturbation theory, the second quantization method and angular momentum theory. The package is built in such a way that it could be applicable in various areas of theoretical atomic spectroscopy. Many functions of the NCoperators can be easily adapted for users to their own demand by transforming the functions developed easily. The package gives the possibility of generating formulas in a traditional output form. For some quantities the expressions obtained in Mathematica can be converted into C code. Although the NCoperators package was developed for Unix OS, it can be easily adopted for other OS if some of the parameters to be changed. Symbolic programming method Mathematica system Atomic Many-Body Theory https://mpm.spbstu.ru/article/2010.12.6/ MPM_9_1_P06.pdf

RAR RUS 53-67 University of Bialystok Breczko

Bialystok, Poland

Belarussian National Technical University, V.V. Barkaline

Minsk, Belarus

Tver State University Grechishkin

Tver, Russia

Belarusian State University of Informatics and Radioelectronics Nelayev

Minsk, Belarus

Magnetic Properties of Ni2MnGa Alloy The paper presents results of the computer simulations and experimental investigation of physical properties of Ni-Mn-Ga alloy. The study was performed using atomic force microscope. The chemical composition of researched specimens causes generation of martensite and austenite phases. Computer simulations are devoted to austenite phase. Ni2MnGa Alloys Magnetic Properties https://mpm.spbstu.ru/article/2010.12.7/ MPM_9_1_P07.pdf

RAR RUS 68-74 Vilnius University Bogdanovich

Vilnius, Lithuania

Vilnius University Štikonas

Vilnius, Lithuania

Vilnius University Rancova

Vilnius, Lithuania

Comparison of Partial Diagonalization of Matrices with Standard Program Complexes Effectiveness of the method of partial diagonalization of matrices created in Department of Theory of Atom at Institute of Theoretical Physics and Astronomy is compared with efficiency of application of corresponding programs from LAPACK and PRIMME libraries. Partial Diagonalization of Matrices Standard Program Complexes LAPACK PRIMME https://mpm.spbstu.ru/article/2010.12.8/ MPM_9_1_P08.pdf

RAR RUS 75-83 University of Warmia and Mazury in Olsztyn Kus

Olsztyn, Poland

University of Bialystok Breczko

Bialystok, Poland

DSC-Investigations of the Effect of Annealing Temperature on the Phase Transformation Behaviour in Ni-Ti Shape Memory Alloy The variations in thermal transformation properties due to annealing within the temperature range from 400°C to 600°C were studied for the near equiatomic Ni-Ti shape memory alloy by the Differential Scanning Calorimetry (DSC) measurements. There was a critical temperature (about 600ºC), where the specimens demonstrated remarkably different transformation courses. There were also noticeable changes in transformation temperatures and heats depending on the annealing temperature. It is thought that the alterations of the microstructure in the Ni-Ti alloy during annealing are responsible for such behavior. Ni-Ti Shape Memory Alloy Phase Transformation Annealing DSC https://mpm.spbstu.ru/article/2010.12.9/ MPM_9_1_P09.pdf