Knowledge Bank

Pure rotational spectra of 17 isotopic species of the van der Waals dimer Xe-CO have been measured with a cavity microwave Fourier transform spectrometer in the frequency region 4.5 - 15 GHz. This dimer has previously been observed in the infrared $region1$. The Xe-CO complex is a near prolate asymmetric rotor. The observed transitions are a-type R-branches, having $\Delta J=+1$ and $\Delta Ka=0$ for levels with $Ka=0$. The derived constants are used to determine an effective structure and to approximate the van der Waals stretching frequency. Comparisons will be made with the properties of other rare gas-carbon monoxide dimers.