Electromagnetic radiation is, far and away, the most interesting aspect of the interaction of matter and energy.

All atomic and molecular motion is thought to be related to electromagnetic radiation in that, to increase the motion, packages (particles) of radiation can be absorbed. This applies to translation, linear motion, but we don't usually concern ourselves with that.

The rotation of molecules involves absorbing microwave energy.

The stretching and bending of chemical bonds involves infrared radiation.

The absorption of light bringing about color involves visible radiation.

Electronic changes involve visible, ultraviolet, and x-radiation.

Changes in nuclear energy levels involve gamma radiation.

Lower of Simon Fraser University has developd a Primer [local] on the Quantum Theory of the Atom.

HyperPhysics contains numerous information sources dealing with quantum effects