Nuclear hyperfine interactions and dynamic state of H2O in Ar–H2O

Rotational spectra for the Ar–H2O dimer have been measured with the Balle/Flygare Mark II pulsed nozzle, Fourier transform microwave spectrometer. The present study extends that of Fraser et al. [J. Mol. Spectrosc. 144, 97 (1990)] to higher resolution, enabling analysis of the hyperfine structure and spin statistics for the Σ(000) and Σ(101) internal rotor states of water in Ar–H2O and Ar–D2O and of the Σ(000) state in Ar–HDO. The results indicate the two internal rotor states to be quite similar, especially for Ar–D2O.