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Analytical Chemistry

University of Missouri, St. Louis

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Full-Text Articles in Physics

First-Principles Calculated Decomposition Pathways For Libh4 Nanoclusters, Zhi-Quan Huang, Wei-Chih Chen, Feng-Chuan Chuang, Eric Majzoub, Vidvuds Ozoliņš Sep 2016

First-Principles Calculated Decomposition Pathways For Libh4 Nanoclusters, Zhi-Quan Huang, Wei-Chih Chen, Feng-Chuan Chuang, Eric Majzoub, Vidvuds Ozoliņš

Physics Faculty Works

We analyze thermodynamic stability and decomposition pathways of LiBH4 nanoclusters using grand-canonical free-energy minimization based on total energies and vibrational frequencies obtained from density-functional theory (DFT) calculations. We consider (LiBH4)n nanoclusters with n = 2 to 12 as reactants, while the possible products include (Li)n, (B)n, (LiB)n, (LiH)n, and Li2BnHn; off-stoichiometric LinBnHm (m ≤ 4n) clusters were considered for n = 2, 3, and 6. Cluster ground-state configurations have been predicted using prototype electrostatic ground-state (PEGS) and genetic algorithm (GA) based structural optimizations. Free-energy calculations show hydrogen release pathways markedly differ from those in bulk LiBH4. While experiments have found …


Rank-Ordering Protein-Ligand Binding Affinity By A Quantum Mechanics/ Molecular Mechanics/Poisson-Boltzmann-Surface Area Model, Mingliang Wang, Chung Wong Jan 2007

Rank-Ordering Protein-Ligand Binding Affinity By A Quantum Mechanics/ Molecular Mechanics/Poisson-Boltzmann-Surface Area Model, Mingliang Wang, Chung Wong

Chemistry & Biochemistry Faculty Works

The authors describe a quantum mechanics/molecular mechanics/Poisson-Boltzmann-surface area model for rank-ordering protein-ligand binding affinity in aqueous solution. Unlike many classical continuum electrostatics calculations in which the protein and ligand are treated as a uniform dielectric, this model uses quantum mechanics to explicitly describe the electronic polarization of the ligand by its environment. In solving the Poisson-Boltzmann equation, the authors use the quantum mechanical charge density directly rather than the common point-charge approximation. The authors show that useful results can be obtained by using experimental structure, by choosing a protein dielectric constant that is smaller than that typically used in classical …