In addition to what Alan F Rawle mentioned, you may calculate the imaginary part of the refractive index by means of a Kramers-Kronig transform. There is free software for doing this! Good luck, Dirk

Akanksha Bhardwaj

As a first approximation, I'd look at Vegard's rule and a linear interpolation.

What sort of alloys do you have:

• Binary/ternary?
• Fully miscible or phase/compound formation
• Dilute systems? Thin films?

Also:

• Can you measure these properties with an ellipsometer?
• To what precision do you need these properties? eV is, of course, directly related to wavelength (which is the normal variable used for RI), and not often expressed to more than 2 decimal places e.g. 1.96 eV is close to the 632.8 nm of a He-Ne laser

In addition to what Alan F Rawle mentioned, you may calculate the imaginary part of the refractive index by means of a Kramers-Kronig transform. There is free software for doing this! Good luck, Dirk

and you may also have a look at the following thread:

https://www.researchgate.net/post/How-can-I-calculate-the-complex-refractive-index-n-and-k-of-polymer-nanocomposites

Alan F Rawle Thankyou for your valuable suggestion Sir. I have binary alloys and going for theoretical study of optical properties of alloys. I need to calculate refractive indices theoretically on nanoscale.

Dirk Luetzenkirchen-Hecht Thankyou Sir for your valuable suggestion and relatable thread. Can you please provide me with the name of the software you have mentioned?

Kind Regards

Akanksha

Akanksha,

please have a close look at

https://www2.mpia-hd.mpg.de/HJPDOC/tools.php

there you'll find additional software and theoretical explanations as well.

Matlab codes are available on the CERN websites (https://cds.cern.ch/record/1338714/files/978-3-540-27316-5_BookBackMatter.pdf)

which may be of help if you are familiar with Matlab.

The University of Twente has executable ready-to-use programs on its download page:

https://www.utwente.nl/en/tnw/ims/publications/downloads/

Dirk van der Marel has several codes for optical calculations on his website

https://dirkvandermarel.ch/science/software-for-optics-2/

including the code for a KK-transform.

An old coding is available in

https://apps.dtic.mil/dtic/tr/fulltext/u2/430722.pdf

I think it is some kind of BASIC programming language, the core of which can however be translated into any other modern language.

So you see, there are pleanty resources freely available, and certainly you'll discover many more if you refine your search, those are only a few which are related to my personal work.

So, go and find out which is best-suited for your purposes, and keep us updated about your progress, best regards, Dirk