Molecular beam magnetic resonance of electronically excited molecules

Molecular beam magnetic resonance of electronically excited molecules 

In chapter 6 we described the theory of molecular electronic states, particularly as it applies to diatomic molecules. We introduced the united atom nomenclature for describing the orbitals, and pointed out that this was particularly useful for tightly bound molecules with small intemuclear distances, like H2. We also discussed the more conventional nomenclature for describing electronic states, which is based upon the assumption that the component of electronic orbital angular momentum along the direction of the intemuclear axis is conserved, i.e. is a good quantum number. The latter description is therefore appropriate for molecules in electronic states which conform to Hund s case (a) or case (b) coupling. 

In this chapter we are concerned with the excited triplet states. The c 3 nu state is the subject of this section, whilst the d and k 3nu states will appear later when we discuss microwave/optical double resonance studies. These triplet states are metastable, 

We first describe the theory of the Zeeman effect and determination of the effective g-factors for bothpara- and ortho-H2, and then proceed to discuss the hyperfine splitting in ortho-Hi- 

The first level to be studied in detail by Tichten [35] was the N = 2 level of both para-Hi and ortho-H2. He measured a series of fixed-frequency magnetic resonance transitions, determining effective g- values and proving the identification of the c3nu state in the process. An effective Zeeman Hamiltonian may be written, in the space-fixed axis system, 

In H2 the ground state electron configuration is described, in the united atom nomenclature, as (l a) with the electron spins paired alternatively the ground electronic state is described as X E+. In the molecular orbital description the ground state electron configuration is. The first excited electronic state in the united 

Molecular beam magnetic resonance studies of H2 in its c state were first described 

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Molecular beam magnetic resonance of electronically excited molecules [1 427... 

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