Infrared and microwave spectra of ne-water complex

The binary complex of rare gas atom and water is an ideal model to study the anisotropic potential energy surface of van der Waals interaction and the large amplitude motion. Although Xe-H$_2$O, Kr-H$_2$O, Ar-H$_2$O, Ar-D$_2$O and even Ne-D$_2$O complexes were studied by microwave or high resolution infrared spectroscopy, the lighter Ne-H$_2$O complex has remained unidentified. In this talk, we will present the theoretical and experimental investigation of the Ne-H$_2$O complex. A four-dimension PES for H$_2$O-Ne which only depended on the intramolecular (Q2) normal-mode coordinate of H2O monomer was calculated in this work to determine the rovibrational energy levels and mid-infrared transitions. Aided with the calculated transitions, we were able to assigned the high resolution mid-infrared spectra of both $^{20}$Ne-H$_2$O and $^{22}$Ne-H$_2$O complexes that are generated with a pulsed supersonic molecular beam in a multipass direct absorption spectrometer equiped with an external cavity quantum cascade laser at 6 $\mu$m. Several bands of both para and ortho Ne-H2O were assigned and fitted using the Hamiltonian with strong Coriolis and angular-radical coupling terms. The predicted groud state energy levels are then confirmed by the J=1-0 and J=2-1 transitions measurement using a cavity based Fourier transform microwave spectrometer