Meaning of de-excite

de-ex•cite

Pronunciation: (dē"ik-sīt'), [key]
— v., -cit•ed, -cit•ing.
—v.t.
  1. to cause (an atom) to fall from an excited energy level to a lower energy level.
—v.i.
  1. to become de-excited.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.