Photodetachment of H- near a Metallic Nanosphere Surface

We investigate the photodetachment of H- near a metallic nanosphere surface over a radius range of 5 to 280 nm. We present the electrostatic image potential of the detached electron caused by the metallic sphere surface, and then we study the classical motion of the photo-detached electron near a metallic sphere surface. The photodetachment cross-section of this system has been derived and calculated based on the closed orbit theory. The radius of the metallic sphere surface and the ion-surface distance have significant effects on the photodetachment of H- near a metallic sphere surface. For a certain ion-surface distance, the oscillating amplitude of the cross-section becomes strengthened as we increase the radius of the metallic sphere surface. In addition, for a given metallic sphere surface, the oscillation in the cross-section decreases with the increase in the ion-surface distance. Hence, we can control the photodetachment of H- near a metallic sphere surface by changing the radius of the sphere or the ion-surface distance. This study provides new understanding on the photodetachment process of negative ions in the presence of a sphere surface or cavities.