Knowledge Bank

Infrared spectra have been recorded for both isomers of the HF-DF dimer, namely where either the HF or the DF act as the proton donor. For the case of HF-DF we have observed both the $Ka=0\leftarrow 0$ and the $Ka=1\leftarrow 0$ sub bands associated with the HF stretch. For the DF-HF isomer only the $Ka=0\leftarrow 0$ sub-band is observed since the proton donor lies very nearly along the A-axis of the complex. Photofragment angular distributions have also been recorded for all three sub-bands, yielding information on the final rotational state distributions. The results agree with the earlier work of HF $dimer1$, which showed with the proton donor molecule is highly rotationally excited while the acceptor molecule is preferentially produced is low j states. Dissociation energies are also reported for both of the isomers and compared with the results of recent theoretical $calculations2$.