Ionic fragmentation of core-excited α-alanine in gas phase was observed. The most dominant ionic species is COOH+ for all core-ionizations at C 1s, N 1s, and O 1s. An increase in COO+ and a decrease in COOH+, which were observed as core-hole atom selectivity for the O 1s ionization, are explained by the enhancement of O-H bond scission. Further state-selective O-H bond scission, observed at the O 1s second peak, is attributed to the OOH 1s → 3s/σ* transition
