115 research outputs found
Compression-induced transformation of aldehydes into polyethers: A first-principles molecular dynamics study
No full textComputational Investigation of the Oxygen Evolution Reaction Catalyzed by Nickel (Oxy)hydroxide Complexes
No full textThe tensile strengths of heterogeneous interfaces: A comparison of static and dynamic first-principles calculations
No full textDensity-functional tight-binding investigation of the structure, stability and material properties of nickel hydroxide nanotubes
No full textToward Improved Electronic Structure of Molecules and Solids: Development Of New Exchange Functionals
No full textThis thesis advances both the methodological foundations and applied frontiers of electronic structure theory toward sustainable energy and environmental applications. It unites the development of new density functional approximations with first-principles design of functional materials, aiming for accuracy, efficiency, and transferability across molecular, solid-state, and low-dimensional systems. The work begins with a rigorous exposition of the many-body problem and the Kohn–Sham density functional theory (DFT) framework, emphasizing the need for accurate exchange–correlation modeling to overcome the limitations of local and semilocal approximations—namely self-interaction, delocalization, and band-gap errors. Building upon this, a generalized formalism for range-separated generalized gradient approximation (GGA) exchange was developed, yielding analytical short- and long-range damping functions and a modular Fortran 90 implementation suitable for hybrid functional construction. The first part of the thesis applies state-of-the-art DFT to clean-energy materials design. Using the HSE06 screened hybrid functional, Cu-doped Ba₃CaNb₂O₉ and Ba₂YNbO₆ were identified as promising visible-light photoelectrocatalysts for water splitting, where Cu substitution and oxygen vacancies jointly modulate the band structure and enhance charge separation. Complementarily, PBE-D3 calculations revealed a new two-dimensional metallic Li₂BC sheet, intrinsically and extrinsically stable, with exceptional hydrogen storage (10.98 wt%), lithium-ion storage (3352 mAh g⁻¹), and pollutant-sensing potential. Motivated by the insights and limitations revealed through these studies, the second part of the thesis advances the methodological frontiers of DFT via the development of new exchange and hybrid models. The Ghosh–Oshi–Salahub (GOS) GGA exchange functional introduces a rational, damping-controlled enhancement factor that satisfies ab initio constraints. Building on this foundation, the Ghosh–Salahub (GS) and Ghosh–Salahub–Gill (GSG) screened hybrid functionals achieve balanced and transferable accuracy across molecular, transition-metal, and solid-state systems. Benchmarks against the Ghosh–Oshi–Salahub-0 (GOS-0) database confirm their performance comparable to, or exceeding, established hybrids such as PBE0 and HSE06. Together, these developments bridge practical materials discovery with theoretical innovation, charting a coherent pathway toward next-generation electronic-structure modeling and sustainable materials design
Molecular structure and interactions of water intercalated in nickel hydroxide
No full textThe structure and properties of α-Ni(OH)2 containing water and nitrate have been investigated computationally.</p
Prediction of reaction barriers and force-induced instabilities under mechanochemical conditions with an approximate model: A case study of the ring opening of 1,3-cyclohexadiene
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