Rydberg states complex molecules

Seen from the point of view of ultra-violet spectroscopy, the situation of aromatic P-, S-, As- and Se-compounds is far more indeterminate than in the t5q)ical oxo and fluoro complexes of the same elements in high oxidation states. Thus, gaseous SFs does not have absorption bands before 95 kK 64) and it is by no means certain that the excited states of these bands involve 3d-orbitals. In many ways, it looks much more as a 4s-like Rydberg state of the whole molecule. 

In absence of Rydbergisation, there are still complexities which can hinder the full development of series. A molecule is a compact assembly of electrons, but (a) is larger than an individual atom and (b) is usually not spherical. Provided the threshold corresponds to a sufficiently stable excited state of the molecular ion, neither (a) nor (b) need prevent the formation of Rydberg states if sufficiently external, the orbitals of the excited electron will only be slightly perturbed by the electrons of the molecular core. Thus, while Rydberg states are often less regular in molecules than in atoms, they can nevertheless extend to very high n. 

The high spectral resolution of the system could also be utilized for measuring autoionisation widths of the Rydberg-valence state complex of the NO molecule in the 11-12 eV region [35]. 

If the value of l is 1, o+ = 2l/2A. This is known as part of the pure precession hypothesis, which is approximately true only for hydrides, Rydberg states of an l > 0 complex, and certain highly ionic molecules (see Section 5.5). Although the pure precession hypothesis is frequently applied to homonuclear molecules, there is no justification for this. 

Molecular Rydberg series are by far more complex than those of atoms. The reason is that many more electronic states exist in molecules, where furthermore each of these states has a manifold of vibrational-rotational levels. Often vibronic levels of different electronic Rydberg states are coupled by several interactions (vibronic, spin-orbit, Coriolis interaction, etc.). This inter-... 

The reaction profile that is displayed in the figures demonstrates the presence of a considerable barrier to the rearrangement of NH4 from a tetrahedral, double Rydberg structure to an anion-molecule complex. In the TS, C3v symmetry applies as one of the NH distances is markedly longer than the others. An additional reduction of symmetry occurs after the transition state with the formation of the hydride-ammonia complex. 

For valence states of nonhydride molecules, there is no reason to expect that the generalized pure precession approximation should be valid. In contrast, Rydberg orbitals, because of their large size and nonbonding, single-center, near-spherical, atomic-like character, are almost invariably well-described by the pure precession picture in terms of nl-complexes. 

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