“…This is attributed to the larger density of states around E F [195]. The influence of rare-gas layers on the properties of image-potential states have been investigated for Xe/Ag(1 1 1) [259,272], Xe/Cu (1 1 1) [262,263,318], Ar, Kr and Xe on Cu(1 0 0) [268,269,273] and Xe/Ru(0 0 0 1) [266,267]. Experimental results for the lifetime of the states are collected in Table 10 for various systems together with predictions from different models.…”