Dear Ashis Manna ,

please go through the basic paper of

L. G. Parratt; at pages 361 and 362:

L. G. Parratt; Surface Studies of Solids by Total Reflection of X-Rays;

Phys. Rev. 95 (2), pp. 359-369 (1954)

I will send you that paper by RG messenger

good luck

thanks @Gerhard Martens

A similar description can be found at:

B. L. Henke; Ultra-soft x-ray reflection, refraction, and production of photoelectrons (100-1000-eV region); Phys. Rev. A6 (No. 1); pp. 94 - 104 (1972)

around equation 36 and the appropriate Figures some pages down

I will send you that paper too....

Thanks a lot @ Prof. Gerhard Martens. It is really a nice paper.

They picked up the example of Au . I am looking for metal oxides, specially ZnO or TiO2. Kindly send me references/link/page if you come across anything related oxides.

All what you primarily need are the optical constants delta and beta of your material for your specifc x-ray wavelength/photon energy. You may calculate these parameters via the stoichiometry of your sample or simply by the following NIST program, which is able to deal with compounds (e.g. ZnO or TiO2) and delivers delta and beta:

http://henke.lbl.gov/optical_constants/getdb2.html

In order to get numbers for delta and beta please change the request for a PLOT into a request for a Text File.

When any troubles in dealing with this program come up, please do not hesitate to request help here...

Good luck