Refractive index of H₂O, D₂O (Water, heavy water, ice)

import lightsmith as ls

# H2O, D2O (Water, heavy water, ice): Afsar and Hasted 1977: Heavy water; n,k 250–2000 µm
h2o_d2o = ls.fetch_refractiveindex("main", "H2O", "Asfar-D2O", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(h2o_d2o.range_nm)  # (250000, 2e+06) nm
eps = h2o_d2o.eps([707000])  # complex permittivity

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_fda3ea5e368a/lightsmith"
h2o_d2o = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(h2o_d2o.source)  # citation and provenance travel with the data

# ... load h2o_d2o as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=h2o_d2o)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=250000, stop_nm=2e+06, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength