Aluminium static Rayleigh weight

The gallery example Al: elastic Rayleigh weight versus density computes a static elastic-scattering weight for aluminium at Te=Ti=10 eV and rho = 2.7, 8.1, 15 g/cc. It uses the public Otter workflow directly and writes PNG and vector PDF copies of the figure.

For each density, the script exports the screening-cloud transform q(k) and ionic form factor f(k) from otter.io.state.build_state_arrays(), uses the one-component Sii(k) from QOZ/HNC, and evaluates

\[W(k)=|q(k)+f(k)|^2 S_{ii}(k).\]

The default mode reads a checksummed archive generated by this exact script, which keeps documentation builds fast. To regenerate all three states, run

OTTER_RECOMPUTE_AL_RAYLEIGH=1 python docs/examples/plot_al_rayleigh_weight.py

The calculation path is entirely in the downloaded example source; no external benchmark runner is imported. q is the charge-closed pseudoatom screening cloud used by QOZ, while f is the bound-electron transform. The ion-structure convention follows Starrett and Saumon (2014), Starrett and Saumon [2014].