Raman K. Singh

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This study shows that the chemical reactivities depend on the orbital energy gaps contributing to the reactions. In the process where a reaction only makes progress through charge transfer with the minimal structural transformation of the reactant, the orbital energy gap gradient (OEGG) between the electron-donating and electron-accepting orbitals is proven(More)
The possibility of quantitative reaction analysis on the orbital energies of long-range corrected density functional theory (LC-DFT) is presented. First, we calculated the Diels-Alder reaction enthalpies that have been poorly given by conventional functionals including B3LYP functional. As a result, it is found that the long-range correction drastically(More)
A wide range of aa'vanced technology for existing and emerging products based on high temperature metal-ceramic composites used in aircrafts, cutting tools, lithium-ion based rechargeable batteries, superconductors, field emission based flat-panel displays, etc. employ micron to submicron sized (0.1-10 microns) particulate precursors in their manufacturing(More)
An orbital energy-based reaction analysis theory is presented as an extension of the orbital-based conceptual density functional theory. In the orbital energy-based theory, the orbitals contributing to reactions are interpreted to be valence orbitals giving the largest orbital energy variation from reactants to products. Reactions are taken to be electron(More)
The difference between the excitation energies and corresponding orbital energy gaps, the exciton binding energy, is investigated based on time-dependent (TD) density functional theory (DFT) for long-chain systems: all-trans polyacetylenes and linear oligoacenes. The optimized geometries of these systems indicate that bond length alternations significantly(More)
Biofuels obtained from renewable resources, such as agriculture residues, woody biomass, sugars crops, and vegetable oils, are attracted because of their effect on the atmosphere is more carbon-neutral and they are less toxic in the environment. Alcohols, biodiesel, biogas are the most common biofuels used today. Bio-oil is a fuel derived from pyrolysis of(More)
The widespread retreat of glaciers can be considered as response to the climate change. Being the largest retreating glacier-ice shelf system in East Antarctica, the Amery Ice Shelf-Lambert Glacier system plays an important role in contributing to sea level rise as well as surrounding environment and climate. The present study is focused on the(More)
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