Vibronic density of states

Let us consider a typical fluorophore, with ground (5g ) and excited (S]) singlet electronic states. The energy states in the vibrational (or vibronic) substructure will be denoted So( 0 ) 5 (C0v), where COy is the vibrational frequency. The lowest energy state in So (S ) is accordingly denoted So(0) 151(0). This vibrational substructure is quasi-continuous for most fluorophores (with say, more than atoms) and can be characterized by a vibrational (or vibronic) density of state Po(Qlv) in So and Po(0)y) in S. ... 

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