It is suggested that quantum‐mechanical tunneling might be used in some instances to provide efficient two‐body collision formation of quasibound molecular states suitable for exciplex laser systems. Some evidence for the existence of the necessary bumps in the molecular potential curves is discussed, and it is noted that potential bumps of the general magnitude and width required are apt to be produced whenever an appreciable cross section exists for endothermic excitation transfer from a metastable state of one gas to an excited state of another gas.