Number 58 (Story #3), December 5, 1991 by Phillip F. Schewe and Ben Stein EVIDENCE FOR CLUSTER IMPACT FUSION swings back and forth. This phenomenon, in which the rate for deuterium-deuterium fusion would be enhanced by many orders of magnitude if a beam of clusters of D2O molecules (rather than free deuterons) were collided with a deuterated target, was first reported by a Brookhaven team in 1989. A new experiment carried out at the University of Washington in Seattle finds no evidence for cluster impact fusion, at least not for small water clusters such as OD-, O2D3-, and O3D5-. (R. Vandenbosch et al., Physical Review Letters, 16 December 1991.)