Arthur Holly Compton physics |

## Compton scattering

When a photon hits an electron, the photon transfers energy to the electron, is deflected and shifts to a lower wavelength. Arthur Holly Compton did the math in which each scattered photon hits only one electron, showing that a photon behaves as a particle, not merely as an electromagnetic wave.

## Compton wavelength

A photon’s energy
is directly related to its frequency.
A particle’s mass
is equivalent to an energy
by Einstein’s formula, *E* = *m*c^{2}.
The Compton wavelength of a particle
is the wavelength of a photon
whose energy is equivalent
to the particle’s mass.
The Compton wavelength
is the amplitude
of the particle’s
Zitterbewegung oscillation.

## Inelastic scattering

When an unstoppable bullet hits an impenetrable wall, the theory disintegrates. There are no such things. Let us rephrase the problem. Our paths shouldn’t depend on which of us is the more stubborn. No bullet’s unstoppable and no wall’s impenetrable. Maybe the bullet can turn corners and maybe the wall is not complete. A little creative thinking, a little kindness and respect, more altruism and less egotism, can stretch the possibilities.

Classical electromagnetic theory predicted that X-rays would not lose energy when scattered. The effect depends on the energy of the photon relative to the energy-equivalent of an electron. Compton scattering is inelastic. It happens when the energy of the photon is higher. Thomson scattering is elastic but happens only when the energy of the photon is much less than the mass energy of the particle (when the particle’s Compton wavelength is much less than the photon’s wavelength).

At the energy of visible light, photons can knock electrons from a surface. This, called the photoelectric effect, supported the concept that energy is quantized.

See also in

The book of science:Quanta—Max Planck, Albert EinsteinSchrödinger equation—Erwin SchrödingerUncertainty principle—Werner HeisenbergDirac equation—Paul DiracZitterbewegung—Erwin SchrödingerReadings in wikipedia: