Structural information from valence-shell PE spectroscopy making assignments

3 Structural information from valence-shell PE spectroscopy making assignments 

The photoelectron spectrum of a molecule is closely related to the set of occupied valence orbitals. For simple molecules, some PE bands show discrete structure due to vibrational excitation of the ion this can be interpreted in terms both of the bonding/non-bonding/anti-bonding character of the electron removed and of the vibration frequencies of the ion, as described in the last section. All of this information is related to 

He(I) photoelectron spectrum of HCl. Redrawn from [6]. Copyright 1970 John Wiley Sons. 

---