Molecular-dynamics simulation of fullerens and nanotubes properties
Carbon is one of the most attractive materials for scientific analysis and industrial applications. It is the basis of all life and of all organic chemistry. The discovery of C60 and the subsequent discovery of other forms of buckeyballs and of carbon nanotubes have opened possibility to create of carbon-based materials with some extremely useful properties.
Nanotubes, depending on their structure, can be metals or semiconductors. They are also extremely strong materials and have good thermal conductivity. The above characteristics have generated strong interest in their possible use in nano-electronic and nano-mechanical devices. For example, they can be used as nano-wires or as active components in electronic devices such as the field-effect transistor for example. Carbon nanotubes and fullerenes are the strongest and stiffest materials on earth, in terms of tensile strength and elastic modulus respectively. This strength results from the covalent sp² bonds formed between the individual carbon atoms. Multi-walled carbon nanotube was tested to have a tensile strength of 63 gigapascals (GPa) (http://en.wikipedia.org/wiki/Carbon_nanotube#Strength). The examples of calculation of strength properties of fullerenes (C60) and nanotubes using MD simulation methods are shown in this interface. More>>
Molecular-dynamics simulation of molecules and atoms
We study the adsorption phenomena and collision phenomena of ions, atoms, and molecules with atoms and molecules. These interactions are not only of fundamental importance but are also essential to the detailed understanding of a broad range of large-scale physical phenomena such as, shock decomposition of energetic materials, fabrication of semiconductor materials, plasma processes, and other. The most common semiconductor industrial material is activated silicon dioxide. Our group has developed new techniques to study adsorption process of silicon atom on silicon dioxide surface. Some results of MD simulation of adsorption processes are shown in this section. More>>
Molecular-dynamics simulation of melting and destruction
The behavior of materials under conditions of extreme temperature and pressure is of significant interest in many fields of physics and chemistry.
To determine and predict the melting point during the shock wave loading of metals is one of the most interesting and actual problems of shock wave physics. Along with experimental and theoretical methods of studying metal melting in shock waves (SW), the molecular dynamics (MD) simulation technique has a certain research potential. Probably, it may be one of the alternative methods to study phase transitions in shock waves.
The process of melting of such metals as Al, Cu, Pb, Pd, and Pt in shock waves was studied using the method of direct molecular modeling. Such an approach directly takes into account the influence of the particular features of shock wave compression upon the parameters of material melting. The Morse potential was used for the description of interatomic interaction. The parameters of the potential were chosen coming out of the condition of correspondence between computational and experimental values of several physical properties of the materials. It is shown that if the metal density increases under compression, the potential which was obtained using the embedded atom method is described quite well by the Morse potential. That is why the latter was chosen to describe the state of matter behind the shock wave front. To determine the point of material melting in the shock wave, it was calculated the dependence of temperature of a shock-compressed material upon the material particle velocity in the shock wave. The analysis of the matter state behind the shock wave front was made with the help of the radial distribution function. The use of modern visualization tools for the MD modeling allowed creating computer films, which serve to visualize and fix the process of material melting in shock waves. The example of MD simulation of aluminum crystal lattice melting under shock wave loading is shown in this interface. More>>