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Experimental studies have been conducted of the radiation emitted by diatomic molecules excited by collision with metastable noble gas atoms. Results indicate that under certain conditions the transfer of energy between the metastable atom and the molecule may be very efficient. The metastable levels of the noble gas atoms are populated through collisions with a collimated beam of high energy $(>10keV)$ electrons. The following molecular systems have been studied: argon-nitrogen, xenon-nitrogen, helium-nitrogen, and argon-carbonmonoxide. Results to date indicate that the transfer of energy is most efficient during a collisional exchange in which the total electron spin and internal energy are conserved. In addition, existing selection rules for the collisional transfer of energy do not predict some of the experimental results.