Excited states Ab initio calculations Ammonia Ammonia molecules Calculations Electronic spectrum Ground state Hydrogen Phenols Polycyclic aromatic hydrocarbons Protonation article A transitions Ab initio Ammonia clusters Ammonia complexes Aromatic compounds Atoms Basis sets C-F bonds CARBON Carbon Charge separation (CS) Charge transfer Charge transfer state Chromophores Conical intersection Diamond films Electron transfer process (ETP) Electronic absorption