Resonant orbital rearrangement

RESONANT ORBITAL REARRANGEMENT DURING F Is IONIZATION OR DECAY PROCESS... 

From the discussions of this chapter, origin of the M line in the F KW Auger spectrum is now well understood, which is the resonant orbital rearrangement, ROR. 

KEY WORDS PIXE, X-ray satellite. Electronic structure. Molecular orbital calculation, DV-Xo, Resonant orbital rearrangement... 

The present author proposed an the approximation method to explain the deviation of the X-ray satellite spectra intensity distributions from those described by eqs.(2),(5),(8) and (10), which we call Resonant Orbital Rearrangement (ROR) [6]. ROR was first used to explain the anomalous intensity distributions in F Ka satellite spectra which are emitted from a series of alkali-fluorides. Here resonance occurs during F Is ionization between the highest occupied molecular orbital (HOMO) in the KT. state and HOMO in the (K L +3s) state corresponding to the lowest unoccupied molecular orbital (LUMO) in the K L state. This leads to a reduction in the K L X-ray satellite intensity and to an increase in the K L X-ray diagram line intensity. Here (K L +3s) denotes the state with one vacancy in K shell and one vacancy in L shell and one electron in a 3s... 

Fig.l2. Resonant Orbital Rearrangement between the HOMO in the K L state and the HOMO in the (K L +3s) state for an element with Z=9 or less. This is a kind of excitation of an electron from the HOMO to the LUMO during Is ionization. 

This simple valence-bond rationale, involving a resonance hybrid of forms 1 and 2, appears to explain many of the physical data available for sulfoxide complexes. It appears that S-bonding does not involve such a major internal rearrangement of the molecule as one may initially expect and is almost certainly a result of the increased orbital diffuseness on passing from oxygen to sulfur. Thus with typical hard acids (see ref. 437), orbital overlap will be most favorable with the less diffuse donor orbital of oxygen. In the case of typical soft metals, this overlap is less favorable due to the orbital diffuseness of the soft acid, and so coordination via sulfur occurs, where the orbital diffuseness of the donor and acceptor are more evenly matched. 

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