Please have a look at:

Article A study of thermal decomposition of sputtered NiO films

Thank you sir for your valuable information.

I have a doubt that, as mentioned in the paper the peaks for oxygen and nickel should exactly matches as given in paper or it can be any value say 0.5 ˚A and 1.5˚A. If so what it suggests sir. Pls let me know sir. it would be useful for my work.

Thank you sir.

The k3-weighted Fourier transformed EXAFS spectra of the as-deposited NiO and annealed films are shown in fig. 2. The best fittings (open circles) are also shown in the figure. The peaks near 1.6 ˚A and 2.6 ˚A in fig. 2(a)–(c), respectively correspond to oxygen and nickel, which is the nearest neighbor of the central atom in NiO.

I must admit that I do not really catch the heart of your question.

All radial distribution functions match the fittings and the R values are consistent.

To my opinion there is no hint that real peaks arising from nearest neighbours could show up between 0,5A and 1,5A in the displayed fourier transforms. The tiny structures observed there are due to artifacts *) in the data evaluation. Real atomic distances in that range are not possible; they should be larger than about 1,5A due to the atomic/ionic radii of the two neighbours. The radii cannot be arbitrarily small.

For typical values of atomic radii please see the following link.

https://en.wikipedia.org/wiki/Atomic_radii_of_the_elements_(data_page)

*) e.g. side lobes of the fourier transform