With the aim of identifying OH bond sites, the yield of photodesorbed
ions from stepped SrTiO3(100)-H2O has been monitored through the Sr N2
,3, 0 L1, Ti M2,3 and Sr M4,5 X-ray absorption edges. Only the Ti M2,3
data provide an unambiguous result, evidencing Ti-OH species. An intr
amolecular OH mechanism appears to dominate the ion yield in the vicin
ity of the Sr N2,3 and 0 L1 edges, and we cannot rule out a majority X
ESD (X-ray induced electron stimulated desorption) contribution to the
ion, yield at the Sr M4,5 edge.