Have you considered chemisorption induced segregation?

yes, in case of alloys we seen oxygen enabled chemisorption of components which are active to oxygen. But I am curious about to know the possibility of inter atomic auger process in metal oxides in such a way that we can probe the oxidation states or other chemical information from that

I hope if inter atomic or inter-molecular auger process occurs while we irradiating an oxide surface with electron or X-ray beam, the possibility for the oxide to under go desorption is there . Hence reduction to lower oxide states will occur by inter- atomic auger decay. This is observed in pentavalent oxides such as Nb2O5, Ta2O5 and also in WO3. The concept have some thing related to chemical passivity of oxides and oxidation kinetics in ambient air to develop a protective oxide. For example the atmospheric oxidation of Ti happens as Ti - TiO  - Ti2O3 - TiO2, we know that TiO2 is the oxide which covers the topmost surface, but are there any importance for the sub oxides TiO and Ti2O3 in the passivation capability of Ti? 

Dear Sherin,

My impression is that the inter-atomic Auger wil not make much effect ion the MNN Auger intensities in Sn as N45 is already  an inner shell hardly involved in chemical bonding.

I am sending you our ancient paper where the question of the intra-atomic contribution to the KVV Auger intencities in HF and  CO molecules had been addressed.  

I remember some older paper on the Ag and Sn MNN- Auger transitions (I think it was in J. Electron Spectrosc. Related. Phenomena) - as far as i have in mind, the effect is due to the different core-hole screening and a resulting change in energy shifts and peak intensities - check by searching this journal.

@ A.G. Kochur - although the inner shells are not involved in chemical bonding, they may be affected by a variation of the chemical bond, as can be easily seen in (hard) X-ray absorption spectroscopy, where e.g. the 1s level binding energies of transition metals change dramatically in energy depending on the oxidation state of the metal, although they are located several keV below the valence band, where the chemistry takes place.

Relative intensities of Auger transitions  don't depend on photon energy

The intensity of interatomic transitions are very small.

In oxidstion state some Sn 4d electrons are removed and the Auger spectrum involving valence shell should be changed.

Since binding energies of 4d3/2 and 4d5/2  are different due to spin orbit coubling, their relative populations in oxide differ from that in pure metal. 

Yours sincerely Victor G.Yarzhemsky

[email protected]

if you want to investigate the chemical state of Sn, it is better to use the XPS. This technique gives directly the chemical shift of core levels and allows to identify the chemical state. Even if the chemical shift of Sn3d peaks between Sn+4 and Sn+2 is rather small, you can use the valence band spectra, which are different for Sn+4 and Sn+2.

See our old paper on this topic:

https://www.researchgate.net/publication/224555656_Surface_Chemistry_of_Tin_Oxide_Based_Gas_Sensors

Article Surface Chemistry of Tin Oxide Based Gas Sensors

To Dirk Luetzenkirchen-Hecht 

You are absolutely right. Of course, the inner-shells levels binding energies are sensitive to the ionic state, and on the electron density of the environment - that's the basic idea of ESCA, isn't it? However the question from Sherin was on the effect of intra-atomic processes on intensities, not energies.

 To V. G. Yarzhemsky 

Hi there, mate! What a meeting! I strongly support your comment

Thanks Dr Rawle, Dr Kochur, Dr Saulius, Dr Yarzhemsky and Dr Dirk for the answers. Happy to see all the great people in core level spectroscopy here in this discussion.

To Dr Yarzhemsky 

According to your opinion, what I understood was there is a possibility for inter-atomic auger transitions to occur in SnO2. I think the valance band of Sn have to deplete completely for auger emission from Oxygen atoms to happen, 

To Dr Dirk Luetzenkirchen-Hecht

I find it out it says about the relation ship between core hole interaction and bandwidth energy. I think in band like spectra interatomic emission can happen because of localization of DOS towards oxygen band, I dont know whether it is true

I think the valance band of Sn have to deplete completely for auger emission from Oxygen atoms to happen,  

Not exactly.

1. deplete not  completely

2. Matrix element for Auger transtion involving two atoms Sn and O is neglogible