Knowledge Bank

The recent laboratory discoveries of submillimeter wave spectra of deuterated hydronium ions, H$2$DO$+$} and HD$2$O$+$,} have opened up the possibility to search for these fundamental deuterated molecular ions in dense clouds where deuterium fractionation occur efficiently. We have used the Caltech Submillimeter Observatory to search for the 0$\mathrm{<mrow\; data-mjx-texclass="ORD">00</mrow>+}$~$\to$~1$\mathrm{<mrow\; data-mjx-texclass="ORD">10</mrow>+}$ transition at 673.257007 GHz in IRAS16293A and Oph D. So far the freezing of CO and N$2$ has been the main issue of the depletion and deuterium fractionation, but this work adds new information on depletion and deuteration chemistry of O and O$2$. Our observational results and analyses will be presented.