Radiationless quantum transition, a quantum transition in which the energy of a quantum system (an atom, a molecule, an atomic nucleus and so on) changes not through the absorption or emission of electromagnetic radiation by the system (that is, as in a radiative quantum transition) but as a result of its interaction with other systems. Thus, in collisions of an atom with another atom, with an electron or with an ion, it may transfer excitation energy or receive it (see Plasma). In a solid, as a result of a radiationless quantum transition the excitation energy of an atom may pass into the energy of vibrations of the crystal lattice (see, for example, Quenching of luminescence).