DIPOLE-MOMENT CALCULATIONS IN MOLECULES WITH CHARGED ATOMS (ZWITTERIONIC FORMS) - MESOMERIC MOMENTS

A practical method of dipole moment calculation of molecules with char ged atoms is presented. The method is a combination of the classical b ond moments additivity method and of electrostatic calculations taking into account interactions between charges and polarizable atoms. The method is tested successfully on simple zwitterionic species and then applied to molecules with mesomeric forms. The conjugation effects are well represented by the method which gives reasonable values for the corresponding mesomeric moments and complementary information on the p ercentages of the mesomeric forms.