15min:

M. REZAEI, J. NOROOZ OLIAEE, N. MOAZZEN-AHMADI, Department of Physics and Astronomy, University of Calgary, 2500 University Dr., N.W., Calgary, Alberta T2N 1N4, Canada; A. R. W. MCKELLAR, National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada.

Infrared spectra of carbon disulphide clusters are studied in the region of the CS_{2 3} fundamental band ( 1535 cm^-1), using a tuneable diode laser to probe a pulsed supersonic slit jet expansion. A symmetric rotor parallel band at 1551.438 cm^-1 is assigned to CS₂ tetramer. The likely structure is a staggered and tilted barrel with D_2d symmetry, similar to the previously observed oblate tetramer of nitrous oxide, in reasonable agreement with that calculated from an empirical CS₂ intermolecular potential function. This is the first high-resolution spectroscopic detection of CS₂ tetramer, and the calculations suggest that there could be other lower energy isomers of (CS₂)₄ which are not yet observed.