I think you might be looking for the Lorentz or Drude models for the materials.  Given just a few physical constants, you can calculate the complex permittivity or refractive index over a wide range of wavelengths.  For a description of the theory and the parameters for some materials, check out Lecture 2 here:

http://emlab.utep.edu/ee5390em21.htm

You probably don't need this, but here is also a short discussion of incorporating the Lorentz-Drude model into FDTD.  See Lecture 10 here:

http://emlab.utep.edu/ee5390fdtd.htm

Thanks for your answer but it has not enough information i have required...i need List of Real and imaginary refractive index,s of Nickel Titanium TiNi Alloy... which is not available in present handbooks of optical constants?

this website can be helpful http://refractiveindex.info/?shelf=main&book=Ti&page=Johnson

i also know about it but it does not provide any info related to TiNI

this website can be helpful http://www.angstec.com/database .  I always take help from it.

see this site, and search your material:

https://www.pvlighthouse.com.au/resources/photovoltaic%20materials/refractive%20index/refractive%20index.aspx