Atomic charges potential

Momany F A 1978 Determination of partial atomic charges from ab initio molecular electrostatic potentials. Application to formamide, methanol and formic acid J. Phys. Chem. 82 592... 

Molecular surfaces can express various chemical and physical properties, such as electrostatic potential, atomic charges or hydrophobicity, using colored mapping. 

Quantum chemical descriptors such as atomic charges, HOMO and LUMO energies, HOMO and LUMO orbital energy differences, atom-atom polarizabilities, super-delocalizabilities, molecular polarizabilities, dipole moments, and energies sucb as the beat of formation, ionization potential, electron affinity, and energy of protonation are applicable in QSAR/QSPR studies. A review is given by Karelson et al. [45]. 

UvHV tff cctivc Diameter V Potential of positive atomic charges... 

Williams D E 1991. Net Atomic Charge and Multipole Models for the Ah Initio Molecula Electric Potential. In Lipkowitz K B and D B Boyd (Editors). Reviews in Computational Chemistr Volume 2. New York, VCH Publishers, pp. 219-271. 

Z1, P Cieplak, W D Cornell and P A Kolhnan 1993. A Well-Behaved Electrostatic Potential Based 5thod for Deriving Atomic Charges - The RESP Model. Journal of Physical Chemistry 97 10269-10280. sen H C, J P M Postma, W F van Gunsteren and J Hermans 1981. Interaction Models for Water in lation to Protein Hydration. In Pullman B (Editor). Intermolecular Forces. Dordrecht, Reidel, I. 331-342. 

Cox S R and D E Williams 1981. Representation of the Molecular Electrostatic Potential by a New Atomic Charge Model. Journal of Computational Chemistry 2 304-323. 

A cubic lattice is superimposed onto the solute(s) and the surrounding solvent. Values of the electrostatic potential, charge density, dielectric constant and ionic strength are assigned to each grid point. The atomic charges do not usually coincide with a grid point and so the... 

In addition to total energy and gradient, HyperChem can use quantum mechanical methods to calculate several other properties. The properties include the dipole moment, total electron density, total spin density, electrostatic potential, heats of formation, orbital energy levels, vibrational normal modes and frequencies, infrared spectrum intensities, and ultraviolet-visible spectrum frequencies and intensities. The HyperChem log file includes energy, gradient, and dipole values, while HIN files store atomic charge values. 

Energy, geometry, dipole moment, and the electrostatic potential all have a clear relation to experimental values. Calculated atomic charges are a different matter. There are various ways to define atomic charges. HyperChem uses Mulliken atomic charges, which are commonly used in Molecular Orbital theory. These quantities have only an approximate relation to experiment their values are sensitive to the basis set and to the method of calculation. 

The above potential describes the monopole-monopole interactions of atomic charges Q and Qj a distance Ry apart. Normally these charge interactions are computed only for nonbonded atoms and once again the interactions might be treated differently from the more normal nonbonded interactions (1-5 relationship or more). The dielectric constant 8 used in the calculation is sometimes scaled or made distance-dependent, as described in the next section. 

Atomic charges and electrostatic potentials Vibrational frequencies IR and Raman spectra NMR properties... 

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