Knowledge Bank

Recently much work has been done on $(H2O)2$ and $(D2O)2$ in the microwave, FIR and infrared regions. We have extended this work by studying some new bands for these dimers in the submillimeter region. In $(H2O)2$ the bands $K=O\to K=1(E1$ and $A1$ symmetry) and $K=1\to K=2(E2$ symmetry) have been measured, while in $(D2O)2$ the bands $K=1\to K=2(E1,A1,B1$ and $E2$ symmetry) were investigated. The dimers were formed in a continuous slit nozzle expansion. The submillimeter radiation was generated either by a tunable FIR laser sideband spectrometer or by direct multiplication of klystrons between 55 and 110 GHz. The measured bands provide valuable information on the A rotational constant and the tunneling splittings for the dimers. In the search for $(D2O)2$, some bands of A$r-D2O$ were found as well, which have not been assigned yet.