Paper SS+AS-WeA2
Confirming the role of Hydrogen Bonding in Electron-promoted Desorption at Water Ice Surfaces.

Wednesday, October 21, 2015, 2:40 pm, Room 112

We have previously reported observations of large (>10^-16 cm²), low-energy (<500 eV), electron-promoted desorption cross-sections for benzene (C₆H₆) molecules adsorbed on the surface of amorphous solid water [1]. We will now report on the extension of this work to other molecular solids exhibiting varying degrees of hydrogen bonding within the molecular solid itself and between the solid surface and adsorbed benzene; specifically we have repeated our measurements employing substrates comprised of solid methanol (CH₃OH) and diethyl ether (CH₃CH₂OCH₂CH₃). Our report will detail our studies of the structure of adsorbed layers of C₆H₆ on the molecular solids and demonstrate the crucial role of hydrogen bonding in propagating electronic excitation to the solid-vacuum interface where C₆H₆ desorption can occur. Competitive electron-promoted chemistry in the form of H₂ formation will also be reported. Conclusions related to the impact of these observations on the early phase of icy interstellar grain chemistry will be discussed.

[1] Highly efficient electron-stimulated desorption of benzene from amorphous solid water ice, J. D. Thrower, M. P. Collings, F. J. M. Rutten, and M. R. S. McCoustra, Chem. Phys. Lett., 2011, 505, 106–111.