Highly efficient electron-stimulated desorption of benzene from amorphous solid water ice

The desorption of benzene ( C 6 H 6 ) from the surface of compact amorphous solid water (ASW) during irradiation with electrons in the range 100–350 eV has been investigated. Two desorption components, with particularly large cross-sections, were present in the observed desorption signal. The fast component, with a cross-section of > 10 - 15 cm 2 , is attributed to desorption of isolated C 6 H 6 molecules that are π -hydrogen bonded to small clusters of water ( H 2 O ) molecules on the compact ASW surface. The slower component, with a cross-section of ca. 10 - 16 cm 2 , is attributed to a more complex desorption process involving larger C 6 H 6 islands on the compact ASW surface. Possible desorption mechanisms are discussed.