Exploring N-rich phases in LixNy clusters for hydrogen storage at nano-scale

We have performed cascade genetic algorithm and ab initio atomistic thermodynamics under the framework of first-principles density functional theory to study the (meta-)stability of a wide range of LixNy clusters. We found that hybrid xc-functional is essential to address this problem as a local/semi-local functional simply fails even to predict a qualitative prediction. Most importantly, we find that though in bulk Lithium Nitride, Li rich phase, i.e. Li3N, is the stable stoichiometry, in small LixNy clusters N-rich phases are more stable at thermodynamic equilibrium. We further show a that these N-rich clusters are promising hydrogen storage material because of their easy adsorption and desorption ability at respectively low (< 300K) and moderately high temperature (> 600K).Comment: 5 pages, 4 figure

Evolution of the Modern Phase of Written Bangla: A Statistical Study

Active languages such as Bangla (or Bengali) evolve over time due to a variety of social, cultural, economic, and political issues. In this paper, we analyze the change in the written form of the modern phase of Bangla quantitatively in terms of character-level, syllable-level, morpheme-level and word-level features. We collect three different types of corpora---classical, newspapers and blogs---and test whether the differences in their features are statistically significant. Results suggest that there are significant changes in the length of a word when measured in terms of characters, but there is not much difference in usage of different characters, syllables and morphemes in a word or of different words in a sentence. To the best of our knowledge, this is the first work on Bangla of this kind.Comment: LCC 201

Lattice analysis of semi-leptonic form factors

We present preliminary results from simulations done on 170 $32^3 \times 64$ lattices at $\beta = 6.0$ using quenched Wilson fermions. This talk focuses on the $Q^2$ behavior of the form-factors, extrapolation in quark masses, dependence on renormalization scheme, and comparison with heavy-quark effective theory (HQET). Even though we cannot estimate errors due to quenching and discretization, our results are consistent with experimental results for $D$ decays. We present results for the Isgur-Wise function and estimate $\xi'(w=1) = 0.97(6)$.Comment: 4 pages. Talk presented at Lattice 95. Latex. Modified "axis" source for figures also include

Exploring semiconductor substrates for Silicene epitaxy

We have carried out first-principles based DFT calculation on electronic properties of silicene monolayer on various (111) semi-conducting surfaces. We find that the relative stability and other properties of the silicene overlayer depends sensitively on whether the interacting top layer of the substrate is metal or non-metal terminated. The nature of silicene-monolayer on the metal termi- nated surface can be metallic or even magnetic, depending upon the choice of the substrate. The silicene overlayer undergoes n-type doping on metal terminated surface while it undergoes p-type doping on non metal terminated surfaces of the semiconductor substrates.Comment: 5 journal pages, 3 figure