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Molecular symmetry in physics and chemistry describes the symmetry present in molecules and the classification of molecules according to their symmetry. Molecular symmetry is a fundamental concept in the application of Quantum Mechanics in physics and chemistry, for example it can be used to predict or explain many of a molecule's properties, such as its dipole moment and its allowed ...
Note that the dipole moments drawn in this diagram represent the shift of the valence electrons as the origin of the charge, which is opposite the direction of the actual electric dipole moment. The bond dipole moment [5] uses the idea of electric dipole moment to measure the polarity of a chemical bond within a molecule. It occurs whenever ...
Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...
Transition dipole moment, the electrical dipole moment in quantum mechanics; Molecular dipole moment, the electric dipole moment of a molecule. Bond dipole moment, the measure of polarity of a chemical bond; Electron electric dipole moment, the measure of the charge distribution within an electron; Magnetic dipole moment, the measure of the ...
The linear electric polarizability in isotropic media is defined as the ratio of the induced dipole moment of an atom to the electric field that produces this dipole moment. [ 5 ] Therefore, the dipole moment is:
The electric dipole moment is a measure of the separation of positive and negative electrical charges within a system: that is, a measure of the system's overall polarity. The SI unit for electric dipole moment is the coulomb-metre (C⋅m). The debye (D) is another unit of measurement used in atomic physics and chemistry.
The ammonia-borane adduct (H 3 N → BH 3) is given as a classic example: the bond is weak, with a dissociation energy of 31 kcal/mol (cf. 90 kcal/mol for ethane), and long, at 166 pm (cf. 153 pm for ethane), and the molecule possesses a dipole moment of 5.2 D that implies a transfer of only 0.2 e – from nitrogen to boron.
Franck–Condon principles can be applied when the interactions between the chromophore and the surrounding solvent molecules are different in the ground and in the excited electronic state. This change in interaction can originate, for example, due to different dipole moments in these two states.