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目前显示的是标签为“Force Field”的博文

Moderated PEF from Transitioning between the Micro and Macroscopic Usage of Coulomb’s Law

Read  full  paper  at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=53278#.VLxuT8nQrzE Author(s)   Eve G. Zoebisch Affiliation(s) Keystone Molecular, Riparian Software, San Diego, USA . ABSTRACT The dielectric constant in Coulomb’s Law, D, can quantify an empirical reduction of force. It can also quantify a reduction of electrostatic field as seen in classical electrostatic theory where the induced charge layer is assumed to be infinitely thin. The two approaches exemplify two traditions that have been used in parallel for decades. They produce Potential Energy Functions (PEFs) that differ by a factor of the permittivity, εr. The classical electrostatic theory result can be incorporated into force field models with an effective dielectric function, Deff, which spans the induced charge layer and accommodates both traditions. The Deff function increases the magnitude of local terms as compared with cumulative long distance ...

A Comparative Study on the Structural and Vibrational Properties of Two Potential Antimicrobial and Anticancer Cyanopyridine Derivatives

Read  full  paper  at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=52999#.VK8-6cnQrzE Author(s)     María J. Márquez , María B. Márquez , Pablo G. Cataldo , Silvia A. Brandán Affiliation(s) Cátedra de Química General, Instituto de Química Inorgánica, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Tucumán, Argentina . ABSTRACT 2-Hydroxy-4,6-dimethylpyridine-3-carbonitrile and 2-chloro-4,6-dimethylpyridine-3-carbonitrile compounds have been studied from a theoretical point of view in order to know their structural and vibrational properties in gas and aqueous solution phases by means of Density Functional Theory (DFT) calculations. The stable structures in both media were optimized by using the hybrid B3LYP/6-31G* method and the solvent effects in aqueous solution were studied by using the integral equation formalism of the polarizable continuum model (IEFPCM) employing the selfconsi...