Reply to ‘‘Question of superoxide inLa2CuO4+δ’’

The arguments of Strongin et al. in the preceding Comment concerning the assignments of O(1s) binding energies in ${\mathrm{La}}_2$ ${\mathrm{CuO}}_{4+\mathrm{\delta }}$ are based upon (1) data from significantly inequivalent samples and (2) assumptions concerning the chemical state of lithium ions frozen on solid oxygen. We reiterate the experimental basis for our original conclusions, clarify the discrepancies, and cite work underway to resolve this issue.