Electronic structure computations dipole moment

The way the electrons distribute in a molecule reflects its physical and chemical properties. For example, dipole moments and electron deficient sites are relevant properties in a molecule that affect the way it interacts with the reaction partners, and these properties are determined by the molecular charge distribution. Quantum mechanics allows the computation of the electron density, which tells the way electrons distribute in the molecule. However, the electron density can only be obtained from an electronic structure computation, and simpler methods are also required to estimate the atomic charges in complex systems. 

Also produced in electronic structure sunulations are the electronic waveftmctions and energies F ] of each of the electronic states. The separation m energies can be used to make predictions on the spectroscopy of the system. The waveftmctions can be used to evaluate the properties of the system that depend on the spatial distribution of the electrons. For example, the z component of the dipole moment [10] of a molecule can be computed by integrating... 

Relative contribution of each of these structures differs significantly and is determined by internal structural characteristics of the nitrones and by the influence of external factors, such as changes in polarity of solvent, formation of a hydrogen bond, and complexation and protonation. Changes in the electronic stmcture of nitrones, effected by any of these factors, which are manifested in the changes of physicochemical properties and spectral characteristics, can be explained, qualitatively, by analyzing the relative contribution of A-G structures. On the basis of a vector analysis of dipole moments of two series of nitrones (355), a quantum-chemical computation of ab initio molecular orbitals of the model nitrone CH2=N(H)0 and its tautomers, and methyl derivatives (356), it has been established that the bond in nitrones between C and N atoms is almost... 

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