Knowledge Bank

Photoionization spectra are reported for $Na2Cl$ and $Na2O$ both of which are formed in a supersonic expansion. Preliminary results for $K2O,Na3O$ and $Na4O$ have also been obtained. Metal clusters are formed by heating sodium or potassium to about $800\circ C$ and expanding the metal vapor along with Ar buffer gas through a tubular nozzle. A reactant gas $(N2O,O2,HCl,orCl2)$ is flowed through an annular nozzle around the tube. Mixing of the two expansions produces $NanO,KnO$ or $NanCl$. Photoionization spectra are measured in the UV region down to a wavelength of 200 nm using a 500 W Xenon lamp coupled with a monochromator set at $33\backslash AA$ resolution. The resulting spectra for $Na2O$ and $Na2Cl$ show that the neutrals are vibrationally hot when ionized. The appearance potential determined for $Na2O$ is about 5.0eV and for $Na2Cl$ is about 3.9eV. The experimental results for these species are compared with theoretical calculations. Both are approximated as systems of three ionic cores with $Na2Cl$ having one valence electron. Appearance potentials were also determined for Sodium and Potassium metal clusters and are in good agreement with other experimental work.