Polarization-dependent dissociation selectively induced by core-electron excitation in methyl ester terminated self-assembled monolayer

Polarization dependence of ion desorption for methyl ester terminated self-assembled monolayer was investigated in carbon and oxygen core-excitations in order to clarify ion desorption mechanism. Site-selective ionic dissociation is induced by the C 1s,O 1s(OCH 3) → σ *(O CH 3) and O 1s(OCH 3) → σ *(C OCH 3) excitations. Ions site-selectively desorbing in these excitations strongly depend on SR incident angle. On the other hand, ion yields in non-selective excitations indicate almost no dependence. Difference in the polarization dependence is considered due to the dissociation mechanisms characterized as direct and indirect dissociation processes.