Molecular mechanics for clusters

For an accurate description of electrostatic interactions, it is necessary to take into account the polarization of the molecules due to the intermolecular interactions. Molecular polarizabilities and hyperpolarizabilities are introduced in the molecular mechanics for clusters (MMC) approach [30]. Several empirical or quantum chemical approaches exist to describe the molecular polarizabilities by atomic or site components [31-47]. The simplest model uses localized dipolar polarizabihties. Such a model can be extended to quadrupolar or higher order polarizabilities. Stone has developed the concept of distributed polarizabilities [36,42]. hi this model, each site of a molecule responds to the... 

The mechanism for cluster formation, and thus the molecular stmcture of the products, is strongly influenced by the special reaction conditions (temperature, type of copper salt used, type and size of the PR3 ligand). As expected very often the thermodynamically stable metal chalcogenides are formed, however, calculations have shown that the PR3-stabilized cluster complexes are metastable. 

Cartesian coordinates system for locating points in space based on three coordinates, which are usually given the symbols x, y, z or i, j, k CBS (complete basis set) an ah initio method CC (coupled cluster) a correlated ah initio method CFF (consistent force field) a class of molecular mechanics force fields CFMM (continuous fast multipole method) a method for fast DFT calculations on large molecules... 

Quantum mechanics is essential for studying enzymatic processes [1-3]. Depending on the specific problem of interest, there are different requirements on the level of theory used and the scale of treatment involved. This ranges from the simplest cluster representation of the active site, modeled by the most accurate quantum chemical methods, to a hybrid description of the biomacromolecular catalyst by quantum mechanics and molecular mechanics (QM/MM) [1], to the full treatment of the entire enzyme-solvent system by a fully quantum-mechanical force field [4-8], In addition, the time-evolution of the macromolecular system can be modeled purely by classical mechanics in molecular dynamicssimulations, whereas the explicit incorporation... 

Yang ZZ, Wu Y, Zhao DX (2004) Atom-bond electronegativity equalization method fused into molecular mechanics. I. A seven-site fluctuating charge and flexible body water potential function for water clusters. J Chem Phys 120(6) 2541-2557... 

To better understand the critical role of oligosaccharide-receptor interactions and their molecular mechanisms through the cluster-effect, and thus access optimized synthetic ligands, several research groups have shown creativity in proposing original multivalent platforms that could allow for tailored valencies, dimensions, and epitope orientations. 

The basic theories of physics - classical mechanics and electromagnetism, relativity theory, quantum mechanics, statistical mechanics, quantum electrodynamics - support the theoretical apparatus which is used in molecular sciences. Quantum mechanics plays a particular role in theoretical chemistry, providing the basis for the valence theories which allow to interpret the structure of molecules and for the spectroscopic models employed in the determination of structural information from spectral patterns. Indeed, Quantum Chemistry often appears synonymous with Theoretical Chemistry it will, therefore, constitute a major part of this book series. However, the scope of the series will also include other areas of theoretical chemistry, such as mathematical chemistry (which involves the use of algebra and topology in the analysis of molecular structures and reactions) molecular mechanics, molecular dynamics and chemical thermodynamics, which play an important role in rationalizing the geometric and electronic structures of molecular assemblies and polymers, clusters and crystals surface, interface, solvent and solid-state effects excited-state dynamics, reactive collisions, and chemical reactions. 

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