Papers by Keyword: Density Functional Theory (DFT) Calculation

Abstract: Hydrogen is a clean, abundant, no-toxic, renewable fuel and packs more energy per unit mass than others. It is important to find a efficient way to store it. Hydrogen molecules adsorbed on the Al doped BN sheets are investigated by using density function theory (DFT) calculations. The results indicate that the H₂ molecule is very easy to be absorbed on the doped BN sheet of B substituted by an Al atom (Al_B-BN), which is most stable structure in all the Al doped configurations. Therefore, AlB-BN is a promising material in storage H₂.

Abstract: Ab-initio calculations have been performed to investigate systematically defect-impurity interaction in Tungsten and other bcc transition metals. It is found that the most stable configuration of C and N atoms is the octahedral interstitial site whereas O and H atoms are located in the tetrahedral configuration. For the particular case of bcc-W, the binding energies formed by the carbon and nitrogen atoms located at octahedral sites, and mono-vacancy on a nearest neighbor site are very large, 1.39 eV and 1.91 eV, respectively. Implication of these results of diffusion of point defects in tungsten is discussed and compared with the case of bcc-Fe.

Abstract: The atomic sulfur adsorption on the metastable, unreconstructed Ir(100) surface is studied from density functional theory calculations with two exchange correlation functionals. The fourfold hollow site is energetically preferred for both the p(2×2) and c(2×2) structures. Based on the most favored adsorption georemetries, vibrational frequency and work function are also calculated. Moreover, a detailed comparison is presented between two functional performances.