Abstract
The many-electron orthogonality catastrophe index for free-electron metals, δ ═ 2(2j+ 1)(δj/π)2, is shown to satisfy constraints including : (i) 0–05 ≤ δ ≤ 0–11, (ii) dδ/dr δ>0, and (iii) consequences of the requirement that δ, the L2 3 threshold exponent α0, and the impurity resistivity be related to the same phase shifts. Values of δ extracted from asymmetric X-ray photoemission lines of Na, Mg, A1, Li, Cs, Cu, Ag, Au, Cd, In and Sn violate one or more of these general constraints. The theoretical and experimental implications of these results are discussed.