Refractive index of (C₂H₄)_n (Polyethylene, PE, HDPE, LDPE)

import lightsmith as ls

# (C2H4)n (Polyethylene, PE, HDPE, LDPE): David et al. 2022: LLDPE film; n,k 2.00–12.3 µm
polyethylene = ls.fetch_refractiveindex("organic", "polyethylene", "David", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(polyethylene.range_nm)  # (1999.96, 12257.5) nm
eps = polyethylene.eps([4950])  # complex permittivity

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_166a6c93a209/lightsmith"
polyethylene = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(polyethylene.source)  # citation and provenance travel with the data

# ... load polyethylene as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=polyethylene)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=2000, stop_nm=12260, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength