Photoelectron Spectroscopy and Through-Bond Conjugation

Construction of the orbitals of N2 using two sp hybrids and two p atomic orbitals on each atom. 

An electron In a molecular orbital is under an effective potential e,-. As we will discuss in Chapter 8, Koopmans theorem shows that the ionization potential required to remove an electron from Is given by —e, [7,8]. As schematically depicted in 6.13, a photoelectron spectrometer measures the kinetic energy of 

6 MOLECULAR ORBITALS OF DIATOMIC MOLECULES AND ELECTRONEGATWITY PERTURBATION 

Photoelectron spectroscopy relates molecular orbital energies, e obtained from molecular orbital calculations to experimentally observed ionization potentials via Koopmans theorem which is usually found to be reasonably accurate for main group compounds using dependable theoretical techniques (transition metal complexes sometimes are problematic). Furthermore, there is not just one peak for a single molecular orbital. As shown In 6.14 each molecule, M, contains a set of 

The photoelectron spectrum for H2 in 6.15 nicely illustrates these features. From the vibrational splitting, an internuciear distance of 1.060 A can be deduced for H2  

---