The electric dipole moment of the Ar2–OCX (X=O,S) complexes Original Research Article

Pulsed nozzle Stark effect Fourier transform microwave (FTMW) spectroscopy has been successfully applied to determine the electric dipole moment of both the Ar2CO2 and the Ar2OCS trimers. For the Ar2CO2 trimer, the dipole moment component was measured to be |μb|=0.1081(1) D, and for the Ar2OCS trimer |μa|=0.2272(2) D and |μc|=0.6448(34) D. Comparing these values with the dipole moments of corresponding dimers, ArCO2 and ArOCS, provides information on how a second non polar Ar atom affects the properties of the dimers. The dipole moment in Ar2CO2 is purely due to polarization effects. In the case of Ar2OCS, polarization effects can be neglected, and from the value of the dipole moment insight can be gained on the zero point oscillations in the cluster.