Site-selective bond scission of methylbenzoate following core excitation

Abstract

The chemical bond scission of methylbenzoate (C6H5CO2CH3) following core excitation at the C and O K edges was examined from partial ion yield measurements across these edges using synchrotron radiation. Site-specific scission of the C-O bonds was observed at both edges. Theoretical X-ray absorption spectra (XAS) were obtained using density functional theory. Peak assignments in the observed spectra were found to be consistent with the theory. From core-excited state dynamics calculations, an elongation of the C-O bond was predicted and provides an explanation of the observed partial ion yield enhancement of CH3+ and C6H5CO+ at the core-excited resonances at both edges.

Site-Selective Dissociation upon Sulfur L-Edge X-ray Absorption in a Gas-Phase Protonated Peptide

“…Core-hole states of molecules composed of atoms with low atomic numbers usually decay via Auger processes, yielding a single- or multiple-valence hole state. In the case of core excitation, SSD may be expected if the resulting valence hole is localized in the vicinity of the initial core hole and if the fragmentation precedes energy redistribution. − On the contrary, it has been shown that the character of the dicationic state of a molecule after core ionization prevents SSD . Site-specific absorption as such has brought deep insight into charge dynamics with the help of X-ray free-electron laser (FEL) facilities. , …”