What happens during classical scatter?

During classical scatter, an incident photon interacts with an atom but does not have enough energy to ionize the atom. This interaction involves the photon changing direction due to the electromagnetic fields of the surrounding electrons, but the overall energy of the system remains conserved, meaning the photon retains its original energy. This results in the incident photon scattering off the electron without causing any ionization, which is a crucial distinction when discussing different types of photon interactions.

The other options describe processes that are not characteristic of classical scatter. For example, the absorption of a photon and the release of energy would involve ionization or excitation, which does not occur in classical scatter. Similarly, an increase in an incident photon's energy does not happen during this type of interaction, as the energy remains constant. Lastly, the complete disappearance of a photon would imply absorption, not scattering, and is inconsistent with the mechanics of classical scatter where the photon still exists after the interaction.