We present the classical and the quantum-mechanical descriptions of surface-state electrons which are perturbed by a periodic force $F\left(t\right)=e\epsilon \Sigma n^{} \delta \mathrm{}(t-T)\mathrm{}$. The numerical results are supported by analytical estimates which indicate that the stochastic behavior which characterizes the classical treatment, and which is manifested by the energy diffusion and ionization rates, is suppressed in the quantum-mechanical treatment.

• Received 11 January 1984

DOI:https://doi.org/10.1103/PhysRevA.30.1040