Experimental 2CH excitation in acetylene-containing van der Waals complexes

Spectroscopic results are presented concerning the 2CH excitation around 1.5 mu m in van der Waals complexes of acetylene (C2H2) with Ar, Kr, N-2, CO2, N2O and C2H2. Many are reviewed from the literature, with some updates. Previously unpublished results are also presented, concerning the mechanism of formation of C2H2-Ar in the supersonic jet, the assignment of new spectral structures in C2H2-N2O, and the first observation of 2CH excitation in C2H2-Ne, C2H2-H2O, C2H2-D2O and (C2H2)(n). Lifetimes of these 2CH vibrationally excited dimers are discussed.