| Clusterization of carbonyl sulphide, OCS, has been investigated by studying the ro-vibrational spectra of its dimer and trimer in a supersonic expansion jet. The study of the nonpolar OCS dimer is extended by observing the infrared spectra of two isotopic forms, (16O12C 34S)2 and (16O13C 32S)2, as well as expansion of the analysis of the normal isotope (16O12C32S)2. In addition, the first observation of the long-anticipated polar isomer of (OCS)2 in the region of v1 fundamental of the OCS monomer is reported. The exact structural determination of the polar isomer of the (OCS)2 is done by studying the infrared spectra of two isotopic forms, (16O12C34S)2 and (16O13C32S)2. Three rotationally resolved infrared bands of the barrel-shaped (OCS) 3, previously known from its microwave spectrum, are observed and analysed for the first time. A plausible assignment for the nature of the OCS vibrations in each of these three bands is discussed. Observation and analysis of two low frequency combination bands of the nonpolar (OCS)2 is also reported. In addition, four more bands are observed and assigned to an asymmetric top with an accidental spherical top structure of the OCS tetramer. |
