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Nguyễn Tiến Cường, Nguyễn Anh Tuấn, Đỗ VănThanh, Nguyễn Hoàng Linh, Nguyễn ThùyTrang, Phạm Hương Thảo, Bạch Thành CôngThe electronic structure and bonding modes of theperovskite oxide BaTiO3 in cubic and distortedtetragonal structures are investigated base on DensityFunctional Theory (DFT). The Density of State (DOS)and Muliken population analyses are brought out inorder to examine Jahn-Teller effect. The results showthat Ti displacement makes the charge transfer from Oatoms to Ba and T atoms. Our results also indicate thatBa atoms play a relatively important role in distributingthe charge transfer.Người trình bày: Nguyễn Tiến Cường96. ComputerSimulation On Local Structure AndDiffusion In System Li2O-SiO2Phạm Hữu Kiên, Vũ Văn Hùng, Phạm KhắcHùng, Vương Thị ThúyThe local structure of liquid (SiO2)x(Li2O)1-x (x =0.1, 0.2, 0.3, 0.4, 0.5) has been investigated usingmolecular dynamic models consisting of 3000 atoms at2200 K. The local structure is analyzed through partialdistribution function (PDF), coordination number andbond angle statistic. The obtained PDFs are in goodagreement with experiment data. The simulation revealsthat most Si atoms are four-fold coordinated, whereasthe coordination of Li atoms are four-, five-, six-fold. Weobserve a clear corelation between the lithiumconcentration and mobility of silicon and oxygen. Thisdata results in the modifying the teterahedral networkstructure by lithium impurity.Người trình bày: Phạm Hữu Kiên97. Computer Simulation Of Interstitial Diffusion InDisordered SystemsTrịnh Văn Mùng, Hoàng Quốc Hoàn, Phạm KhắcHùngThe direct calculation of diffusion in atomistic modelswith know interaction potential between impurity andmatrix atoms is a long standing problem in glassscience. A new calculation method overcoming therestriction of non-force method is applied to simulatediffusion in Lennard–Jones models and also in theregular disordered lattice. The size effect and theArrhenius behavior for both amorphous and crystallinemodels are examined and discussed here. The simulationreveals some specific properties for interstitial diffusionin amorphous solids compared to crystal. In particular,we observe the close value of activation energy foramorphous and fcc models, meanwhile the preexponentialcoefficient of amorphous solid is similar toone of bcc crystal.Người trình bày: Trịnh Văn Mùng98. High Harmonic Generation Spectra of BasicBases of DNA Interacting with Ultra-ShortLaser PulsesThành phố Đồng Hới (03- 06/8/2009) Trang 83/ 102Thành phố Đồng Hới (03- 06/8/2009) Trang 84/ 102