Desorption has been induced on CsI by hydrogen clusters of mass ranging from 5 to 23. A cluster effect has been observed in comparison of the ${\mathrm{Cs}}^{+}$ desorption yields as obtained from intact and preexploded clusters. The variation of the yield with the sum of the electronic stopping powers of the cluster components (additive stopping) shows a fourth-power dependence. The contribution of collective effects in the interaction may play a crucial role in the nonlinearity of the process.

• Received 20 December 1984

DOI:https://doi.org/10.1103/PhysRevLett.55.103