Knowledge Bank

Spectra of acetylene-carbonyl sulphide trimers in the region of the OCS \nub{1} fundamental ($\sim$2062\backslash wn)areobservedusingatunablediodelasertoprobeapulsedsupersonicslitjetexpansion.Apreviousmicrowavestudyof(OCS)$_2$-C$_2$H$_2$ by Peebles and Kuczkowski \textbf{111}, 10511 (1999).} gave a nonplanar triangular twisted structure, which could be thought of as a polar OCS dimer plus a C$2$H$2$ monomer lying above the dimer plane. In the present work, three infrared bands are analyzed. The first band clearly belongs to this previously known (OCS)$2$-C$2$H$2$ complex. The second band can be assigned as an isomer of (OCS)$2$-C$2$H$2$ having a similar structure, but with a nonpolar OCS dimer plus a C$2$H$2$ monomer above the dimer plane. The third band is assigned to OCS-(C$2$H$2$)$2$. The rotational constants and dipole moment components of all three bands are consistent with barrel shape structures having C$1$, C$2$ and C symmetries, respectively.