Motivational factors The nature and degeneracy of vibrations The legitimate AO combinations for MOs The appearances and absences of lines in a molecules spectrum o The polarity and chirality of a molecule. 20218/21 Chemistry Departme nt of Fudan UniversityPhysical ChemistryI Chemistry Department of Fudan University Chapter IV Molecular Symmetry and Point Group 2021/8/21 5 The nature and degeneracy of vibrations. •The legitimate AO combinations for MOs. •The appearances and absences of lines in a molecule’s spectrum. •The polarity and chirality of a molecule. Motivational Factors