PROTON TUNNELING IN MOLECULAR-SOLIDS

Low-temperature optical spectroscopy of guest-host molecular crystal s ystems gives direct access to proton tunneling processes. Examples inc lude the photo-induced creation and evolution of ''proton defects'', a s well as translational tunneling along hydrogen bonds and rotational tunneling of methyl groups. The first observation of the effect of rot ational tunneling on conventional absorption spectra is reported For g amma-picoline single crystals.