# SPDX-FileCopyrightText: 2026 John C. Travers and contributors
#
# SPDX-License-Identifier: MIT

"""
Argon: the fitted model
=======================

The argon model (``fit/Ar``): the 104.8 nm and 106.7 nm resonance lines at their NIST
energies and two effective oscillators, with the magnetic susceptibility :math:`\\chi_0
= -2.30\\times10^{-4}` a.u. that makes the electric polarizability the refractive one.
The absolute level comes from Lesiuk & Jeziorski's ab initio Cauchy moments, the
dielectric static polarizability (Gaiser & Fellmuth, via Lesiuk) and Egan's
refractometry at 633 nm, which agree to a few 1e-5; the shape from 468 nm to 2.06 um
from Peck & Fisher, whose level is 3.5e-4 high and is fitted free; the vacuum
ultraviolet from Bideau-Mehu and Gordon. Squares are validators, not fitted: Zhang's
comb value at 800 nm (+2.6e-4), Birch at 633 nm, Borzsonyi, Rusch's infrared point, and
the Lyman-alpha values of Gill and Heddle.

Top: direct datasets against the fit, with the fit's one-sigma band. Configured data
use the fitter's conventions and uncertainties, with fitted scales removed; electric
data receive the magnetic term for this comparison. Middle: the published formulas,
the recorded ``luna_physdata`` fit and refractiveindex.info's entries against the
fit. Bottom: the fitted direct datasets' normalised residuals; the static dielectric
point agrees within one sigma. See :doc:`/fitting` for the panel definitions."""

# %%
from _helpers import fit_overview

fig = fit_overview("Ar", xlim=(100e-9, 20e-6))