Recurrence Spectra of the Rydberg Hydrogen Atom near Two Parallel Metal Surfaces

Using closed orbit theory, we study the influence of the two parallel metal surfaces on the recurrence spectra of a hydrogen atom placed in the region between the two surfaces. The results show that the metal surfaces have significant effect on the photoabsorption process. Each resonance peak in the recurrence spectra is associated with one electronic closed orbit. In our work, we put the first metal surface at the critical value d_c and vary the second metal surface. The results show that when the distances between the hydrogen atom and the two metal surfaces are close to the critical value d_c, the number of the closed orbits is the greatest and there are more peaks in the recurrence spectra. When the distance between the atom and the second metal surface is larger or smaller than d_c, the number of the closed orbits decreases and there are fewer peaks in the recurrence spectra. The agreement between the semiclassical alculation spectra and the quantum calculation spectra suggests that our analysis is correct.