Molecular-Dynamic Code to Simulate the Properties of Materials With Covalent Chemical Bonds (SAGE MD)

A. Yu. Aleynikov, N. S. Ganchuk ( gan-AT-socc-DOT-ru.gif ), P.V. Yermakov, A. A. Korkin*, A. A. Selezenev
Sarov Open Computing Center, Sarov 607190, Nizhni Novgorod Region 607190, Russia.
*SPS Motorola, DigitalDNA Laboratories, MD EL722, 2100 E Elliot Road, Tempe AZ 85284, USA

Molecular dynamics code SAGE MD is designed for modeling of chemical and physical properties of materials by the classical molecular dynamics method. The code has been written in FORTRAN 90, a part of the code has been written in MS VC++. A friendly user interface has been added to the code. The user interface allows setting all initial data for SAGE MD code using the dialogues and menu. The result of all operations with crystal lattice during generation of initial geometry of MD cell is displayed on the monitor allowing the user to control the correctness of his/her actions. During setting the initial geometry of the crystal the following operations may be applied to the selected part of the crystal lattice: copying, transfer, axis turn to the specified angle, deletion, scaling, changing of atom type. The user interface allows also displaying the atoms position in MD cell during calculation, as well as displaying all calculated values in form of diagrams after calculation is complete. The SAGE MD code can be used to model the properties of materials at constant temperature and/or constant pressure, as well as to simulate the behavior of materialís crystal lattice exposed to extension or compression. The calculations of Radial Distribution Function (RDF) and atoms diffusion coefficient are implemented in the code. Different boundary conditions can be set during modeling: periodical boundary conditions, free surfaces, and movable walls. The interatomic interaction model taking into account the charges distribution on atoms (QEq model) has been incorporated into SAGE MD code to simulate the properties of the materials with covalent chemical bonds. The following interatomic potentials are also incorporated into SAGE MD code: Morse, modified Morse, Bukingham, Embedded Atom Method (EAM), Stillinger-Weber, Tersoff B, Tersoff C, Maruyama. The code has been tested by comparison of the MD modeling results with the known experimental values of the physical characteristics of silicon and silicon oxide.