کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1240641 | 969133 | 2007 | 7 صفحه PDF | دانلود رایگان |
The photoionization of uranium via three-step excitation has been optimized for isotope selective trace analysis. A search found 13 new J = 6, 7, and 8 odd-parity states in the 36,850–37,200 cm− 1 region that allow blue–red–red three-photon excitation at wavelengths favorable for commercial diode laser systems. From each of these 13 states, near-threshold autoionization spectra were recorded at a resolution of 3 × 10− 4 cm− 1. Some 30 even-parity autoionizing levels with J = 5 to 9 have also been observed and characterized. Comparison of the spectra allows J assignment for the new intermediate levels as well as selection of an optimized path for trace analysis. We show that, for a chosen scheme using a narrow J = 9 autoionizing resonance at 49,972 cm− 1, all of the excitation steps can be saturated with powers available from single-mode cw diode laser systems when exciting an atomic beam in perpendicular geometry.
Journal: Spectrochimica Acta Part B: Atomic Spectroscopy - Volume 62, Issue 5, May 2007, Pages 485–491