Why dont you observe a compton effect with visible light?

Answer 1

Photons propagating at frequencies in the visible light spectrum can knock out electrons from atoms, known as the photoelectric effect, if their energy is greater than the photoelectric work function for that atom. However, at the energies associated with the visible light frequencies, these new photoelectrons will absorb any excess energy of the initial photons and convert it to kinetic energy, meaning that the initial photons vanish. Obviously, if the photons are gone, they can't scatter. Increasing the intensity (brightening) of the photons will cause more electrons to be emitted, but it will not increase their energy since photon energy is a function of its frequency, not quantity.

Photons that retain energy after interacting with an electron via the photoelectric effect are said to undergo Compton scattering. Now, despite what everyone says, if a photon has any amount of energy greater than the applicable photoelectric work function, it can theoretically undergo Compton scattering. Yes, I'm implying that visible light can Compton scatter. However, the probability of Compton scattering at these energies is very low, not to mention these scattered photons would most likely loose all of their energy from all of the other various available atomic interactions before they could even escape the sample, which is a necessary component to measurement (something has to exist in order to be measured). Therefore, the effects of Compton scattering are negligible at visible light energies. In fact, they don't really start becoming noticeable until around energies of 100keV, which is around 105 times greater than the energies associated with visible light. These kinds of energies are associated with x-rays.