Observation of the A(2)Sigma(+)<- X-2 Pi electronic transition of NaO

The gas-phase infrared spectrum of the A(2)Sigma(+) <-- (XII)-I-2 electroni c transition of the NaO radical was observed for the first time utilizing t unable diode laser differential absorption spectroscopy; 109 lines were fou nd within the region 2015-2095 cm(-1) and 45 lines within 2654-2696 cm(-1). The NaO radical was produced by reaction of sodium vapor with N2O in a fas t flow tube and detected using an astigmatic Herriott multipass absorption cell combined with rapid sweep integration absorption signal processing. Si mple kinetic studies were performed in order to differentiate the NaO radic al features from precursor N2O lines. The NaO A(2)Sigma(+) <-- (XII)-I-2 vi bronic band structure was modeled using ab initio calculations by Langhoff and co-workers; the simulated NaO band profile agrees reasonably well with that observed. A preliminary assignment of some observed lines and the resu lting molecular constants are presented. Quantitative absorption strength m easurements indicate that either absorption line strengths for this transit ion are significantly smaller than indicated by ab initio calculations or t he Na + N2O reaction produces a significant fraction of NaO(A) state which resists collisional quenching under our experimental conditions.