Hello Sir,

XRD technique gives clear idea about lattice dimension so that we can find out whether it belongs to nano level..In the technique diffraction patterns from different planes are spotted and the peak will give the lattice parameters of diffracting planes (edge length)..They are two types Small and wide angle technique..just take the XRD spectra of your sample and that will say your sample will fall in nano dimension..

All the best

I'm not sure that I understand your question.

But I see two way for solve your problem:

1. If you know what is your NP compaunds, then XRD pattern for this compund and comparison your data with patterns. 

2. Also you can use spesific software: Match! (for exemple). 

For taken the diameter of your NP use Debye-Sherrer’s equation. 

Are you intersted to find the entire crystal structure (space group, lattice parameters and atomic positions) or only lattice parameters? It is a little bit different problem..

Dear

There are many programs for find the lattice parameter such as standard Rietveld method.

The study in the link below has done this, have a read. They have very good data considering that these are supposed to be nanoparticles. They used the FullProf Rietveld software to find the lattice parameters. If you want more detail than that - it starts getting more complex - what do you really need?

please note - there is no such thing as the Debye-Scherrer equation. It is just the Scherrer equation. This mistake is getting copied and copied and is now even in journals whose reviewers and editors should know better. It will not give you the diameter of the nanoparticle unless one particle is also one coherent scattering domain. It is possible for one particle to be composed of a number of scattering domains. You would need to use HRTEM to verify this.

http://www.hindawi.com/journals/jns/2013/929321/