Complete characterization of the (D2O)(2) ground state: High K-a rotation-tunneling levels

We report the observation of extensive a- and c-type rotation-tunneling (RT ) spectra of (D2O)(2) for K-a = 0-4. These data allow quantification of mol ecular constants and tunneling splittings for a number of previously unobse rved RT states of (D2O)(2). The vibrational ground state has thus been char acterized to energies as high as those of some of the intermolecular vibrat ions, and we present the first test of the VRT(ASP-W) potential at these hi gh K-a states.