Reflectivity

Reflectivity refers to the measurement of the intensity of reflection off of a flat interface. The term both describes the physical phenomenon, as well as the experimental technique.

X-ray Reflectivity (XRR or XR) and neutron reflectivity (NR) are techniques which measure the intensity of reflected radiation as a function of angle (where, by definition for specular reflectivity, the incident and exit angles are equal; $\scriptstyle \theta _{i}=\theta _{f}$). A plot of reflectivity (R) versus angle yields the reflectivity curve. For XR and NR, the data is typically plotted as a function of the momentum transfer parallel to the film normal:

$q_{z}={\frac {4\pi }{\lambda }}\sin \theta$

Reflectivity calculation for a thin film.

Off-Specular Reflectivity

TBD

See Also

• Fresnel plot
• Oscillations below the critical angle
• DWBA: A formalism for modeling GISAXS data, including reflection effects.