My apologies for the delayed reply. I am guessing that you are interested in looking at something like the transmission or reflection spectra of Au nanoparticles. If you want to model the effect of temperature on optical behavior, this can be done in our optical solvers (both FDTD Solutions and MODE Solutions) using the index perturbation material. The index perturbation material allows users to modify the index of any material as a function of charge variation of temperature variation. To learn how to create an index perturbation material take a look at the bottom of this KB page: https://kb.lumerical.com/en/index.html?ref_sim_obj_index_perturbation_material.html.
The general workflow in your case would be,
- Create index perturbation type materials for each of the material in your simulation setup whose index you think would be affected by temperature variation.
- Set the simulation temperature to the desired value. This is a property of the solver region and can be accessed by going into the property editor of the solver.
- Run the simulation.
A few points to consider would be,
i) You will need to know how the index of your materials vary with temperature. You can either use a linear model and define a temperature coefficient or you can use a table to input the variation to index as a function of temperature variation. For more details take a look at this kX post: How to perturb refractive index as a function of temperature.
ii) A more important point to consider (and I am not sure about this) is whether you can expect to see any effect of temperature on the behavior of the nanoparticle (specially as such small variation in temperature) simply because the variation of material index due to temperature is usually very small.
Hope this helped. If you have any questions let me know.