excited state

noun Physics.

1. any of the energy levels of a physical system, especially an atom, molecule, etc., that has higher energy than the lowest energy level.

n.

1. The condition of an atom or molecule after absorbing energy from exposure to light, electricity, elevated temperature, or chemical reaction, and which may be a necessary prelude to a chemical reaction or to the emission of light.

1. A state of a physical system in which the system has more than the minimum possible potential energy. Excited states tend to be unstable and easily or spontaneously revert to lower energy states, giving off energy. Compare ground state.