Spurious oscillations from local self-interaction correction in high-energy photoionization calculations for metal clusters

We find that for simple metal clusters a single-electron description of the ground state employing self-interaction correction (SIC) in the framework of local-density approximation strongly contaminates the high-energy photoi onization cross sections with spurious oscillations for a subshell containi ng node(s). This effect is shown connected to the unphysical structure that SIC generates in ensuing state-dependent radial potentials around a positi on where the respective orbital density attains nodal zero. Non-local Hartr ee-Fock that exactly eliminates the electron self-interaction is found enti rely free from this effect. It is inferred that while SIC is largely unimpo rtant in high photon energies, any implementation of it within the local fr ame can induce unphysical oscillations in the high-energy photospectra of m etal clusters pointing to a general need for caution in choosing appropriat e theoretical tools.