Compton Effect

X-ray scattering off of free electrons.

The scattering intensity is expected to be the same as the incident and the frequency does not change.

But experiments show a change in frequency/ wavelength!

• $\delta \lambda =4\pi {\lambda }_C{\sin }^2\frac{\theta }{2}$
• ${\lambda }_C=\frac{\hslash }{m_{e}c}$