We argue that spontaneous microchannel $S$-matrix correlations and slow spin decoherence result in a sensitivity of the cross sections for strongly dissipative heavy-ion collisions to an arbitrarily small perturbation. Such a sensitivity implies that atomic electrons should influence energetic $\left(\simeq 100\mathrm{MeV}\right)$ heavy-ion reactions. The atomic-electron effects are predicted to be $\simeq 100\%$ of the magnitude of the non-self-averaged oscillating component of the nucleus-nucleus cross sections.

• Received 20 November 1998

DOI:https://doi.org/10.1103/PhysRevLett.84.423