Névot–Croce roughness factor
Effect of RMS surface roughness on specular reflectivity — NC = exp(−q
z
² σ²)
q
z
(nm⁻¹):
NC(σ) = exp( −q
z
² · σ² )
σ = RMS surface roughness (nm) · q
z
= 4π sin(θ)/λ · NC = 1 is perfectly smooth, NC → 0 is fully diffuse