The excimer emission of aromatic hydrocarbons on clays

The emission of some aromatic hydrocarbons on die surface of hectorite (Laponite and SHCa-1) and montmorillonite (SWy-1, Volclay, STx-1 and Syn-1) clays was studied. p-Terphenyl, biphenyl and naphthalene, when adsorbed on clays showed excimer emissions, as well as the well-known molecular fluorescence bands, but on SWy-1 and Volclay the emissions were relatively weak. As the loading was increased, the excimer emission tends to dominate the emission spectra, particularly for the montmorillonites STx-1 and Syn-1. Emission due to microcrystals on the clay surface was also detected at larger loadings. No excimer emissions were detected for m-terphenyl and 1,1'-binaphthyl even at the larger loadings used. (C) 1998 Elsevier Science S.A. All rights reserved.