Electronic spectra

This chapter focuses on the concept of electronic spectra. Electronic spectra arise from transitions between the electronic energy levels of molecules, which may also be accompanied by simultaneous changes in vibrational energy. The chapter then looks into the Laporte selection rule and the Franck-Condon principle in correlation with the electronic transition in a nuclear framework. It also considers the vibrational fine structure and rotational fine structure as the structures in a spectrum that arises from changes in vibrational energy and rotational energy respectively. Moreover, as the chapter shows, charge-transfer transitions typically involve the migration of electrons between the ligands and the central metal atom.