Heat-Pipe Oven for Homogeneous Mixtures of Saturated and Unsaturated Vapors; Application to NaLi

A heat-pipe oven has been developed to produce homogeneous mixtures of a saturated vapor with an unsaturated vapor at any arbitrary well-defined ratio. The oven is able to handle materials of widely different vapor pressures and the zone containing the homogeneous vapor mixture can be made to extend over any desired path length. With this heat-pipe oven containing sodium and lithium, the laser- and collision-induced fluorescence spectrum of the NaLi molecule has been used to study the operation of the oven. The first observation of a ``propensity rule'' for a polar molecule (the ΔJ=+1 collision-induced NaLi line is stronger than the corresponding ΔJ=−1 or 0 line) is reported.