4d core hole formation in silver and its role in Ag secondary ion formation/survival

The low energy mono-atomic secondary ion intensities of Ag⁻ over the transient regions from Ag under 1-5 keV Cs⁺ primary ion impact are compared. These energies are used since they appear to be above and below the collisional excitation threshold for 4d core hole formation. The lack of any work function dependence in both suggests that (a) Ag⁻ forms via resonance charge transfer of electrons from the broad 5s-5p band to Ag atoms bearing 4d core holes (Auger is disregarded for energetic reasons), and that (b) the route via which 4d core holes are formed, whether it be via collective oscillations or collisional excitation, is of minimal importance. The similarity in X-ray induced plasmon loss features from clean and Cs implanted Ag confers with these results.