Refractive index of Propanee soot

import lightsmith as ls

# Propanee soot: Dalzell and Sarofim 1969: n,k 0.4358–10 µm
propane_soot = ls.fetch_refractiveindex("other", "propane_soot", "Dlazell", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(propane_soot.range_nm)  # (435.8, 10000) nm
eps = propane_soot.eps([633])  # complex permittivity

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_4b3e78eeb916/lightsmith"
propane_soot = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(propane_soot.source)  # citation and provenance travel with the data

# ... load propane_soot as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=propane_soot)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=436, stop_nm=1000, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength