Rotational spectrum of the isotopically substituted van der Waals complex Ar-CO2 investigated with a molecular beam Fourier transform microwave spectrometer

Pure rotational spectra of the isotopomers Ar-(OCO)-O-16-C-13-O-16,Ar-(OCO)-O-17-C-12-O-16 and Ar-(OOO)-O-18-O-12-O-16 of Ar-CO2 have been investigated using a molecular beam Fourier-transform microwave spectrometer. The analyses of the experimental data yielded rotational and centrifugal distortion constants. These data were included in a force field analysis which has resulted in values for van der Waals stretching and bending force constants and harmonic vibration frequencies. In the case of Ar-(OCO)-O-17-C-12-O-16, hyperfine structure of rotational transitions due to the quadrupolar O-17 nucleus was observed and the corresponding nuclear quadrupole coupling constant could be determined. The obtained data are discussed in terms of structural and dynamical parameters.