The energy in a single particle of visible light is often just that amount needed to do a nice bit of chemistry. Nature takes supreme advantage of this synergy and teamwork in photosynthesis, the process so essential to all life on the planet.
Spectroscopy delves into the interaction of light, visible and invisible, with matter.
Light can be absorbed or emitted. Particularly with lasers, other processes are possible. The wide range of spectroscopic techniques available may be utilised as analytical or diagnostic tools, right down to the single molecule level. At a more fundamental level, spectroscopy provides potent methods with which to probe the innermost secrets of all chemical species. Spectroscopy also maps out the detailed electronic structure of matter.