Kawazoe Laboratory Seminars

Year 2016
[1] 2016-04-13 (Fri) @3rd floor in Hatchery Square
13:30- Prof. K.-H. Chew ( Center for Theoretical Physics, Department of Physics, University of Malaya 50603 Kuala Lumpur, Malaysia)
Title: Ab Initio Molecular Dynamics Study of Reaction Pathway from Iron (III) Hydroxides to Hydrated-Iron (III) Oxides: A Preliminary Study

[2] 2016-July-27 (Wednesday) @3rd floor in Hatchery Square From 15:00-
Prof. Abhishek Kumar Singh, Indian Institute of Science, Bangalore
Title; Pt-Poisoning-Free Efficient CO Oxidation on Supported Pt3Co Catalysth.

[3}2016-08-3 (Wednesday) @3rd floor in Hatchery Square From 15:00-
Prof. Talgat Inerbaev
Titile; DFT study of copper ordering in Al-Cu alloy

Old data
Year 2013 Seminar Schedule of Kawazoe's Research Group

2013-05-13 (Mon) @3rd floor in Hatchery Square
[1] 13:30- Dr. Y. Y. Linag Title: Electrons through the Nano Structures: A First-principles Simulations by using TOMBO Abstract: Following the Moore's law, the size of electric devices becomes smaller and smaller. However, if the dimension of the device is small enough, the quantum phenomena will be dominant. Different candidates, such as the organic molecules, carbon nano tubes and graphene have been considered as the prospective materials to be used as the new devices. To understand the electron transport through these materials on the density functional theory basis, we devoted to developing the first-principles software package based on Tohoku University Mixed-Basis Program (TOMBO). TOMBO uses plane wave and atomic orbitals as the basis sets. In principle, plane wave cannot be used directly to simulate the electron transport problems. To overcome this difficulty, we introduce the Wannier function into TOMBO and calculate the current through the nano systems by non-equilibrium Green's function.

2013-05-20 (Mon) @3rd floor in Hatchery Square
[2] 13:30- Dr. R. V. Belosludov Title: Theoretical Study of Nanoporous Materials to Gas Storage Applications Abstract:i Formalism for calculating the thermodynamic properties of a clathrate hydrate with weak guest-host interactions was realized for energy storage applications. Using this approach, the phase diagrams of the pure and binary hydrogen hydrates was constructed and they are in agreement with available experimental data. In order to evaluate the parameters of weak interactions, a time-dependent density-functional formalism and local density technique entirely in real space have been implemented for calculations of vdW dispersion coefficients for atoms/molecules within the all-electron mixed-basis (TOMBO) approach. The combination of both methods enables one to calculate thermodynamic properties of clathrate hydrates without resorting to any empirical parameter fittings. Using the proposed method it is possible not only confirm the existing experimental data but also predict the unknown region of thermodynamic stability of clathrate hydrates, and also propose the gas storage ability as well as the gas composition for which high-stability region of clathrate hydrates can be achieved. The proposed method is quite general and can be applied to the various nanoporous compounds with weak guest-host interactions.

2013-05-27 (Mon) @3rd floor in Hatchery Square
[3] 13:30- Dr. V. J. Surya Title: Investigation of Hydrogen Storage in Carbon based Nanostructured Materials Abstract: Fuel cells based on hydrogen, the simplest element and most plentiful gas in the universe are more efficient and non-pollutant than the current internal combustion engines based on fossil fuels. The hydrogen economy mainly relies on five factors namely production, storage, transportation, conversion, and applications. My research focuses mainly on hydrogen storage/delivery. The performance targets of a hydrogen storage system for light-duty vehicles were developed by U. S. department of energy (DOE) and the targets remain as a "Grand Challenge" to the scientific community. Solid state storage is considered to be the most promising way than other conventional methods of hydrogen storage. A nanotechnological approach to solve the problem of storing hydrogen for fuel cells is the main theme of this theoretical research drive. Principal attention is paid on carbon nanomaterials like SWCNTs, graphene and C60 fullerene to store hydrogen. The results and conceptions drawn from this research work mainly assist the scientists to devise new hydrogen storage materials that will satisfy the U. S. DOE targets.

2013-06-03 (Mon) @3rd floor in Hatchery Square
[4] 13:30- Dr. Yaocen Wang Title: Ab initio simulation of FeSiB(PCu) amorphous alloy Abstract:The structures of Fe83Si7B10 and Fe76Si9B10P5 amorphous alloys were simulated by DFT approach. Clusters can be recognized in the resulted structure while the short range ordering can be observed from partial pair correlation function (PPCF). Some of the magnetic property in Fe76Si9B10P5 amorphous alloy can also be calculated with certain degree of accuracy. Local Chemistry of Fe85Si2B8P4C1 and distribution preference of Fe76Si9B10P5 are also calculated.

2013-06-10 (Mon) @3rd floor in Hatchery Square
[5] 13:30- Prof. Fabio Pichierri Title: Environmental computational chemistry of Cesium-137 Abstract: With the aid of both DFT calculations and chemical knowledge we can suggest possible strategies for the removal of radioactive Cs-137 from the contaminated environment. I will explain how this can be done by employing macrocycles that can bind the alkali metal ions through non-covalent interactions.

2013-06-17 (Mon) @3rd floor in Hatchery Square
[6] 13:30- Dr. Arkapol Saengdeejing Title: A computational study of the bcc Fe-Si system: thermodynamic and structural properties study Abstract: First-principles calculations, based on density functional theory, are employed to investigate both phase stability and structural properties of the Fe-Si system in bcc structure. Focusing on the Si-dilute bcc Fe, elastic properties of Si-doped bcc-Fe between 0 to 12.5 at.%Si have been calculated. Electronic structures as well as basic structural, magnetic and thermodynamic properties at di erent concentrations have been evaluated and analyzed to obtain better understanding of mechanism behind the variation in yield strength of Si-doped bcc-Fe as the Si content increase. Temperature dependent of the elastic properties at selected concentrations will be calculated using Debye-Gruneisen model to estimate the elastic properties at finite temperature. Elastic constants calculations are based on the stress-strain method.

2013-06-24 (Mon) @3rd floor in Hatchery Square
[7] 13:30- Prof. Keivan Esfarjani (Rutgers University) Title: Thermal conductivity of chalcogenide compounds

2013-07-01 (Mon) @3rd floor in Hatchery Square
[8] 13:30- Prof. Tamio Ikeshoji Title: Bias imposed interface between solid Li ion conductor LiBH4 and Li metal: first principles molecular dynamics simulations Abstract: LiBH4 was found to be a fast ionic conductor at T > 390 K (Li+ conductivity, ? = 5 ÁE10 E S cm E at 423 K) [1], where it changes from an orthorhombic to a hexagonal structure. It shows a reversible electron transfer between Li+ and Li metal. It has a large electrochemical window, though it is a strong reducing agent. First principles molecular dynamics (FPMF) simulation showed that hexagonal LiBH4 originates from the atom occupation splitting in the c-direction that results in a dumbbell-like density profile [2]. Activation barrier between two sites was found to be lower than 0.01 eV. A Li atom, at first, moves to a metastable interstitial site by thermal excitation, leaving a vacancy [3]. The metastable-state is at 0.29 eV higher energy and the barrier surrounding it is at 0.30 eV. Then, another Li atom moves to this vacancy through a connection region having a barrier of 0.31 eV. In these FPMD, a finite basis DFT (density functional theory) code, FEMTECK, was used. In order to see the LiBH4 electrolyte and Li metal interface under a bias, we need a scheme to apply the electric field (or to give a charge to the interface region) in the electronic structure calculation under the periodic boundary conditions. We used ESM (effective screening medium) method for it after implementing the method to a standard DFT calculation code STATE (plane-wave basis set with ultrasoft pseudopotential and GGA (PBE) exchange correlation) [4]. Calculation is for the system of 60~90 Li atoms with bcc (100) or (110) surface and 80 LiBH4 units in the high temperature phase. It is sandwiched by ESM(metal) and ESM(vac.) as we have done for the Pt | water system. Time step and temperature of FPMD is 1.2 fs and 410 K, respectively. When a bias is applied to the LiBH4 and Li metal interface, occupancy of Li atoms in the double well potential of LiBH4 changes from 1:1. Its change is reversible with no memory effect. This polarization is almost linear to the strength of the bias. This polarized structure on electrode may be a reason of the reversible electron transfer reaction of Li+ + e E?? Li. An evidence of electron transfer in this interface is also found in the FPMD. 1. M. Matsuo, Y. Nakamori, S. Orimo, H. Maekawa, and H. Takamura, Appl. Phys. Lett., 91, 224103 (2007). 2. T. Ikeshoji, E. Tsuchida, K. Ikeda, M. Matsuo, H.-W. Li, Y. Kawazoe, and S. Orimo, App. Phys. Lett., 95, 221901 (2009). 3. T. Ikeshoji, E. Tsuchida, T. Morishita, K. Ikeda, M. Matsuo, Y. Kawazoe, S. Orimo, Phys. Rev. B, 83, 144301 (2011). 4. M. Otani, I. Hamda, O. Sugino, Y. Morikawa, Y.Okamoto, T. Ikeshoji, J. Phys. Soc. Jpn, 77, 024802 (2008).

2013-08-01 (Thu) @3rd floor in Hatchery Square
[9] 13:30- Prof. Gang CHEN (School of Physics and Technology, University of Jinan) Title: Catalytic properties of near-surface alloy of transition metal in aluminum: A density functional theory study on structural and electronic properties