Free Sodium-Water Clusters

Abstract

Neutral sodium-water clusters are formed in a "pickup" source, injection of a beam of Na atoms into the expansion zone of a pulsed nozzle-jet beam of water vapor seeded into an argon carrier gas. They are detected by near-uv one-photon ionization with a pulsed laser and time-of-flight mass spectroscopy. $\mathrm{Na}{\left({\mathrm{H}}_2\mathrm{O}\right)}_n$-cluster-ion signals up to $n=12\mathrm{}$ are seen, $n=4\mathrm{}$ showing a very pronounced abundance. The ionization potential of NaO${\mathrm{H}}_2$ is determined to be 4.379 ± 0.002 eV.