60 research outputs found
Electrophilicity Equalization Principle
A new electronic structure principle, viz., the principle of electrophilicity
equalization is proposed. An analytical justification as well as a numerical
support for the same is provided.Comment: 9 pages, 2 table
Aromaticity in Polyacene Analogues of Inorganic Ring Compounds
The aromaticity in the polyacene analogues of several inorganic ring
compounds (BN-acenes, CN-acenes, BO-acenes and Na6-acenes) is reported here for
the first time. Conceptual density functional theory based reactivity
descriptors and the nucleus independent chemical shift (NICS) values are used
in this analysis.Comment: 4 pages, 2 figures, 2 table
Minimum Magnetizability Principle
A new electronic structure principle, viz. the minimum magnetizability
principle (MMP) has been proposed and also has been verified through ab initio
calculations, to extend the domain of applicability of the conceptual density
functional theory (DFT) in explaining the magnetic interactions and
magnetochemistry. This principle may be stated as, "A stable
configuration/conformation of a molecule or a favorable chemical process is
associated with a minimum value of the magnetizability". It has also been shown
that a soft molecule is easily polarizable and magnetizable than a hard one.Comment: 2 Pages, 3 Figure
Hydrogen (H2) Storage in Clathrate Hydrates
Structure, stability and reactivity of clathrate hydrates with or without
hydrogen encapsulation are studied using standard density functional
calculations. Conceptual density functional theory based reactivity descriptors
and the associated electronic structure principles are used to explain the
hydrogen storage properties of clathrate hydrates. Different thermodynamic
quantities associated with H2-trapping are also computed. The stability of the
H2-clathrate hydrate complexes increases upon the subsequent addition of
hydrogen molecules to the clathrate hydrates. The efficacy of trapping of
hydrogen molecules inside the cages of clathrate hydrates depends upon the
cavity sizes and shapes of the clathrate hydrates. Computational studies reveal
that 512 and 51262 structures are able to accommodate up to two H2 molecules
whereas 51268 can accommodate up to six hydrogen molecules.Comment: 21 pages, 5 figures, 6 table
A philicity based analysis of adsorption of small molecules in zeolites
Adsorption of small molecules like CH4, CO and NH3 into the acid sites of zeolites is analysed as an interaction between an electrophile and a nucleophile. Global reactivity descriptors like softness and electrophilicity, and local reactivity descriptors like the Fukui function, local softness and local philicity are calculated within density functional as well as Hartree-Fock frameworks using both Mulliken and Hirshfeld population analysis schemes. The HSAB principle and the best electrophile-nucleophile combination suggest that the reaction between the NH3 and Bronsted acid site of the zeolite is the strongest. Interaction between the zeolite and a small probe molecule takes place through the most electrophilic atom of one with the most nucleophilic atom of the other. This result is in conformity with those provided by the frontier orbital theory and the local HSAB principle
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