New Dissociation Channels inD2O

Making use of a novel solid xenon matrix detector which is selectively sensitive to $\mathrm{O}(^{1}S_{0})$ metastable atoms, a new dissociation channel, via a $^{1}A_{1}$ repulsive state, has been uniquely identified following electron impact on ${\mathrm{D}}_{2}\mathrm{O}$ molecules. Careful measurements of the O fragment kinetic energies and appearance potentials have allowed partial reconstruction of the potential energy surface involved. The excitation function for production of $\mathrm{O}(^{1}S_{0})$ has a shape which is characteristic of an optically allowed transition in the parent molecule and has a maximum value of $1.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}18}{\mathrm{cm}}^{2}$ at 100 eV incident electron energy.