Refractive index of PtSe₂ (Platinum diselenide)

import lightsmith as ls

# PtSe2 (Platinum diselenide): Ermolaev et al. 2021: 300 nm film; n,k 0.245–3.30 µm
ptse2 = ls.fetch_refractiveindex("main", "PtSe2", "Ermolaev", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(ptse2.range_nm)  # (245, 3300) nm
eps = ptse2.eps([633])  # complex permittivity

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_4052f1bde43d/lightsmith"
ptse2 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(ptse2.source)  # citation and provenance travel with the data

# ... load ptse2 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=ptse2)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=400, stop_nm=1000, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength