Natural SciencesChemistryPhysicsMolecular PhysicsPhysical ChemistrySpectroscopyElectronic SpectroscopyElectronic StructureMolecular Orbital TheoryMolecular SpectroscopyMolecular StructurePolyatomic MoleculesElectronic Absorption SpectraElectronic Structure AnalysisElectronic Structure Of MoleculesElectronic Structure TheoryGround State PropertiesPolyatomic Molecular VibrationsVibrational Band Structure