Surface-induced dissociation of methanol cations: A non-ergodic process

Dissociation of methanol molecular cations, CH 3 OH + , to CH 2 OH + on collision with a self-assembled monolayer surface of fluorinated alkyl thiol on gold 111 crystal has been studied at 12.5 eV collision energy. Two energetically and spatially distinct processes contribute to the dissociation process: one involving loss of very large amount of energy approaching the initial kinetic energy of the primary ions with scattering of fragment ions over a broad angular range between surface normal and surface parallel while the second process results from small amount of energy loss with fragment ions scattered over a narrow angular range close to the surface parallel. There is a third process with relatively small contribution to total dissociation whose characteristics are very similar to the low energy loss process. These results demonstrate that surface-induced dissociation of methanol cations via hydrogen loss is non-ergodic.