Image states in metal clusters

TL;DR

This paper demonstrates the existence of image states in small metal clusters using a quantum-mechanical approach, providing energies and wave functions, and introduces a semiclassical model for larger clusters.

Contribution

It presents the first detailed GW-based calculations of image states in spherical jellium clusters and proposes a semiclassical model for mesoscopic cluster sizes.

Findings

Image states exist in small metal clusters.

Quantum confinement affects image states.

A semiclassical model agrees with GW results.

Abstract

The existence of image states in small clusters is shown, using a quantum-mechanical many-body approach. We present image state energies and wave functions for spherical jellium clusters up to 186 atoms, calculated in the GW approximation, where G is the Green's function, and W the dynamically screened Coulomb interaction, which by construction contains the dynamic long-range correlation effects that give rise to image effects. In addition we find that image states are also subject to quantum confinement. To extrapolate our investigations to clusters in the mesoscopic size range, we propose a semiclassical model potential, which we test against our full GW results.