Isotope effects in H+(D+) desorption induced by 4a1 ← O 1s resonant transition of condensed H2O (D2O)

Auger electron–photoion coincidence (AEPICO) experiments have been performed for condensed water (H2O and D2O) at the 4a1 ← O 1s resonant transition. Several kinds of isotope effects were observed in H+ (D+) desorption, they were, (1) the differences in ion kinetic energy for the selected Auger-final-states, (2) the relative intensity differences in AEPICO spectra, (3) peak shifts in AEPICO and resonant Auger electron spectra and (4) the intensity difference in prominent peak in ion yield spectra. Those isotope effects can be explained by a four-step ion desorption mechanism involving O–H (O–D) bond extension within the lifetime of the O 1s core-hole.