The electric dipole moment of the Ar-2-OCX (X = O,S) complexes

Pulsed nozzle Stark effect Fourier transform microwave (FTMW) spectroscopy has been successfully applied to determine the electric dipole moment of bo th the Ar,CO, and the Ar2OCS trimers. For the Ar2CO2 trimer, the dipole mom ent component was measured to be \mu(b)\ = 0.1081(1) D, and for the Ar2OCS trimer \mu(a)\ = 0.2272(2) D and \mu(c)\ = 0.6448(34) D. Comparing these va lues with the dipole moments of corresponding dimers, ArCO2 and ArOCS, prov ides information on how a second non polar Ar atom affects the properties o f the dimers. The dipole moment in Ar,CO2 is purely due to polarization eff ects. In the case of Ar2OCS, polarization effects can be neglected, and fro m the value of the dipole moment insight can be gained on the zero point os cillations in the cluster. (C) 1999 Elsevier Science B.V. All rights reserv ed.