Observation of Br₂ stretch modes of adsorbed molecules on various substrates

We report the observation of the Raman modes of Br₂ molecules bound to graphite, KBr and fused quartz substrates. The results demonstrate that Br₂ bonds to surfaces at preferred sites, except in the case of fused quartz, where no unique site can be defined owing to its amorphous nature. The spectra of Br₂ on the KBr substrate, taken at later times, exhibit modes that are related to a chemical modification of the KBr substrate.