Educate me please, Why Absorption of Co(III) complex having lower than Co(II) complex. What are important things behind this.
This because the crystal field stablization energy of Co(III) with d6 is higher than forCo(II) withd7 arrangement
No, X-ray absorption deals not with the excitation of VALENCE electrons but with the excitation of CORE electrons (usually K (1s) and L 2s,2p shell) and the energy required to remove an electron is firstly correlated to the shell where it is located (this is why you need to know in advance at which edge (K or L) you want to measure) and secondly to the attractiive force between the electron and the nucleus. The attraction and thus the required energy is larger, the higher the charge of the atom you look at.
Prof., Axel Klein., Thanks for nice explanation with your experience view. by Rajkumar. K.
yes, i mean absorption for metal ion, as XANES is oxidation sensitive to small structural variations.However, atoms with a higher oxidation state require more energetic X-ray to excite its core electron because the nucleus is less-shielded and carries a higher effective charge,where as the absorber–scatterer distance gets shorter, the energy of the continuum state increases as 1/R2. Since higher oxidation-states implies shorter bond lengths , the edge energies increases .
Amira you are right! Normally, higher oxidation state of a materials goes along with slightly higher edge energy. In your case it seems to be reversed and maybe it has to do with the coordination and the spin state. Did you check the spinstates of these two materials? Generally, low spin ions are markedly smaller than corresponding high spin species.
OK. prof i agree with you; Changing of charge distribution leads to changing of the chemical environment of the absorbed atom; and the absorption edge will shift in the XANES regime because the core-level energies are changed; every molecule have their distinct charge distributions . However, there are a lot of physical effects evolved in the near-edge region.
Dear Experts.,
I need with your own experienced view and clarification for the following question.
Reaction : Cu(II) salt used for adsorption and doped progress on metal oxide surface.
Q1 : What happens in oxidation state and edge energy of Cu ion ?
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