Core-electron excitation and fragmentation processes of hydrogen bonded acetic-acid clusters in the oxygen K-edge region

▶ Core-electron excitation spectra and fragmentation processes of acetic-acid clusters. ▶ O1s(CO) → π*CO transitions shift by +0.37/−0.92 eV upon cluster formation. ▶ Hydrogen-bond strength of RCOOH clusters determines the cluster-band shift. ▶ We propose “local-fragmentation” and “low-energy MnX+ formation” mechanisms. ▶ Fragmentation after electronic relaxation follows either of these two mechanisms.