The first step forms Al 4+ (1s -1 ) ions and initiates a decay cascade, where ~90% of the ionized species undergo local KLL AugerMeitner decays to predominantly (~63%) form Al 5+ (2p -2 ) states. Alternatively, a single Al 2p level vacancy can be created by initial ionization at lower photon energy (2p -1 ). These 2p vacancies are filled by nonlocal ETMD processes, in the case of Al 4+ (2p -1 ) in one ETMD {}_{2{{{\rm{p}}}}}^{-1\to {{{\rm{GS}}}}} step, and for Al 5+ (2p -2 ) in two steps, ETMD {}_{2{{{\rm{p}}}}}^{-2\to 2{{{\rm{p}}}}}^{-1} followed by ETMD {}_{2{{{\rm{p}}}}}^{-1\to {{{\rm{GS}}}}} , after which the Al ion is back to its ground state Al 3+ (GS). Each ETMD process ionizes up to two water molecules and emits one slow ETMD electron. Note that, for clarity, the figure only shows ETMD processes involving two water molecules, ETMD(3); for further details, see the main body of text.
