Measurements of vibrational predissociation of SF6 clusters are discussed and compared with theoretical spectra. Attention is given to the line-shape and saturation behaviour as influenced by spatial averaging effects. Also isotopic dimers are considered. Hyperfine-structure measurements of H 2-H2, H2-Ne, H2-Ar and H 2-Kr dimers are dealt with, and information from these results concerning the intermolecular potentials is discussed.@en