For the purpose of exploring microscopic structures and functions of molecules, crystals and soft condensed matters in the atomic size （１Angstrom), we adopt quantum mechanical simulation method that relies on the density functional theory. 　It describes electrons within atoms and molecules by their density via the Kohn-Sham equation. This method is thus called ab initio or first principle molecular dynamics (FPMD)simulations. 　　We are refining this first principle code to treat atomic movement and also material deformation through chemical reactions. This type of the simulation codes is required to study microscopic behavior of materials at the interface of high temperature fusion plasmas without making a priori assumptions, unlike the case of macroscopic transport codes. (Collaboration with Dr. Y.Zempo). 　　The left figure shows the FPMD run of 　hydrogen atoms adsorbed to the graphite surface.　These hydrogen atoms cut the bonds between carbons at the surface, make a hydrocarbon atom, which runs away from the graphite surface.　Figure: A sequence of the final states of graphite surface due to addition of one hydrogen atom at a time. Gray and white spheres represent carbon and hydrogen atoms, respectively (calculated using the Siesta code, developed by ICMAB group, Spain). 　Because of increasing complexity, the Schroedinger equation, which exactly describes every electrons can be solved only up to five electrons.　However, real material consists of a huge number of electrons (and nuclei), and such a system is virtually insolvable even with the fastest supercomputer.　On the other hand, if one treats electrons collectively through their density instead of wave functions of each electron, the equation becomes much simpler and solvable (density functional theory).　This method is widely adopted for studies of physical properties and chemical reactions on the atomic level.

　 First Principle Molecular Dynamics Code by Density Functional Theory

　　　　Graphite Erosion by Hydrogen Adsorption