Mechanisms Of Site-Specific Photochemistry Following Core-Shell Ionization Of Chemically Inequivalent Carbon Atoms In Acetaldehyde (Ethanal)

Site-specific fragmentation upon 1s photoionisation of acetaldehyde has been studied using synchrotron radiation and a multi-electron-ion coincidence technique based on a magnetic bottle. Experimental evidence is presented that bond rupture occurs with highest probability in the vicinity of the initial charge localisation and possible mechanisms are discussed. We find that a significant contribution to site-specific photochemistry is made by different fragmentation patterns of individual quantum states populated at identical ionisation energies. Published by AIP Publishing.