Beams of D2O clusters with 10∼1000 eV per deuterium yield unexpectly high fusion rates. This is an energy range intermediate between hot and cold fusion, and as such may serve as a link bridgin the two regimes. We present a theoretical model capable of explaining apparently conflicting experimental results with beams of D2O clusters in which fusion rates higher than expected were observed, and beams of D clusters in which no fusion was observed. Calculated results indicate that total deuterium‐deuterium fusion rates can be enhanced by many orders of magnitude by the use of deuterium‐heavy atom cluster beams. A set of experimental test is proposed.