Dear Rajesh,

Your need to obtain a high-quality XPS core-levels and valence band spectra with a BG beeing subtracted. Unfortunately, from Your data it is not possible to realize what oxidation state the copper has. Please, have a look, for instance, http://xpssimplified.com/elements/copper.php

There the difference is very strong for detection and the following conclusions.......

Or, please, have a look our manuscript "Valence states of copper ions and electronic structure of LiCu_ {2} O_ {2}" that is presented here, at researchgate.net (or similar manuscript). Sorry, I can't to attach the PDF of our paper due to some browser problems. Thus giving web-link.

https://www.researchgate.net/publication/235469695_Valence_states_of_copper_ions_and_electronic_structure_of_LiCu__2_O__2

In our manuscript it was shown how to determine the unknown valence states of copper in multinary compound.

Comment: The BE is not the only signature for oxidation, because BE value might be distorted due to differential charging of the sample while performing an XPS (depends on the band-gap of the sample and the charge neutralizer of employed XPS spectrometer) - improper charge neutralization or wide band-gap material or/and both reasons. More presicely will be comparing both BE and spectrum shape with reference sample (the sample with a known valence state of copper - the so-called XPS external standard).

One more comment: It is very hard to detect the difference among Cu-metal (Cu^(0)) and Cu^(1+) using XPS (though the other oxidation states of copper are well determined by XPS method). Thus it is the need to apply additional technique for sure, if Cu-metal is suspected in a material under study.

Hope it will be useful.

Regards,

Dmitry

Article Valence states of copper ions and electronic structure of Li...

Dear Dr. Dmitry,

Thanks for providing useful information. 

Welcome at any time. :)

With regards,

Dmitry

you need to get an XPS spectrum with higher resolution and better background. Still, I consider that the assignment of the chemical species is not entirely correct, because, to what you call Cu ion, are really satellites Cu oxide. 

You can Use this reference, greetings

https://www.researchgate.net/publication/259094299_Determination_of_the_Cu_2p_primary_excitation_spectra_for_Cu_Cu2O_and_CuO

Article Determination of the Cu 2p primary excitation spectra for Cu...

2 J.A. Torres-Ochoa

Exactly so! Fully supporting Your answer. The attached reference is very good, valuable, and relatively "fresh".

Regards,

Dmitry

Sorry, I  forgot about the manuscript presented below - this will be some additive to my previous answer, Mr. Rajesh.

This also might be interesting in order to catch the XPS signature of small reduction of CuO to Cu_2O (or the very beginning of the reduction process) - the transformation of shake-satellites in Cu 2p core-level spectra.

https://www.researchgate.net/publication/225477828_Phase_transformations_in_CuO_caused_by_bombardment_by_He_ions_and_by_the_action_of_spherical_shock_waves

This manuscript is demonstrating that while the reduction of CuO to Cu_2O occurs, the "CuO XPS satellites" are not disappearing immediatly but they are sequentially diving in intensity (this effect was caught in cooperation with Dr. V.R. Galakhov, Russian Academy of Science, Russia and Prof. M. Neumann, University of Osnabrueck, Germany).

Why I have mentioned about it ? Because the Cu^(2+) -> Cu^(1+) transition might be not completed up to the very end, and, thus, the mixed-valence copper will be present simultaneously, so the "CuO XPS satellites" will be still exhibited in Cu 2p core-level spectra but with dissimilar intensity and shape in comparance with that for "pure" Cu^(2+) material (see Fig.1 of the reported paper).

It is very important for correct XPS analysis of the sample under study!

On the whole, IMHO, it is very nice XPS effect (and very fine ! - needs very accurate XPS measurements) and, probably, will be interesting to You, Mr. Rajesh, for the future XPS Materials Science.

(Please, don't think that it is an advertising of our papers  :) ).

Regards,

Dmitry

Article Phase transformations in CuO caused by bombardment by He+ io...

Dr. Torres-Ochoa and Dr. Dmitry,

Thanks for interesting references, and your explanations.

Really glad to be helpful to my Collegues from India.

Now it is much better, Rajesh. But, please, subtract the BG....

Regards,

Dmitry

Thanks Dr. Dmitry. Finally, I made it in better way with the help of your discussions and references. How can subtract the BE ?

Using software like A-Analyzer, CASA XPS, or what so ever....

BG = background, not binding energy.

Regards,

Dmitry

Thanks Dr. Dmitry,

I will do the same. I think, now it looks better to send it for publication.

Good Luck, Rajesh. Hope it will be accepted.

Regards,

Dmitry

Thanks,

 How can we differentiate Cu(II) coordinated with some support and Cu(II) of CuO from XPS analysis?

I need one more clarification Dr. Dmitry. The explanation and results are attached for your perusal.

Your need to do something like this.... Please, have a look the attached figure.....

You need to measure at Your XPS system the reference samples - XPS external standards - "pure" CuO and "pure" Cu2O - the materials which are respectively affor onlu Cu2+ and Cu1+. It will be not a good idea to use "external" spectra for these materials because the conditions of XPS measurements, resolution, BG, etc. - they are dissimilar. Thus I recommend to do it at Your XPS system - in the same conditions as was measured Your sample under study.

After that Your need to subtruct the BG. If it is not easy for Your, I can do it for You, if You will send to me the data file for Cu 2p XPS. We have some program for that (it was hand made) which I am not responsible to distibute it. The file have to be in ASCII format - two colums, energy and Intensity. Of course, this is only if You will agree....

My email is [email protected] for direct messaging.

Comment: Please use all the time Al Ka XPS source for measurements and apply multypoint spectrum recording with the following summation - this will be much better than one point and long-time exposition. Copper 2+ compounds are VERY SENCITIVE for external affect and a reduction to Cu1+ might occur. So it will be the question - whether it was reduced from the very beggining (due to sample preparation) or it is a sequence of a long-time X-ray exposition in XPS spectrometer... This is VERY INPORTANT!

With regards,

Dmitry

seems to me You have "CuCl2", but not "CuO" or "Cu2O" in Your samples... Please have a look attached figure. Especially, please compare the shapes of satellites in Cu-halogens.... They are very close in shape to what You have. CuO Cu 2p has strongly dissimilar satellites.......

Regards,

Dmitry

Dear Dmitry,

Thanks for your support. We don't have XPS facility, I get it done some where. It may be difficult for me to analyze pure CuO and Cu2O in same XPS conditions. I am learner in XPS technique. Your suggestions are helping to improve my knowledge. Sure, I will contact you, if I need any help in this regard.

Sincerely

Rajesh

It's up to You....

Regards,

Dmitry