Association reactions of Na+ and some implications for interstellar chemistry

Three-body association reactions of Na(+) with a variety of neutral gases in the presence of He as third body have been studied in a SIFT at 80 K. The measured rate coefficients have been utilized to estimate radiative association rate coefficients at 20 K. It is shown that Na(+)/neutral radiative association reactions play a role in the depletion of Na(+) in dense interstellar clouds and can produce a sufficient amount of NaOH to explain its observed tentative abundance in Sgr B2.