鋰原子D1譜線超精細結構和同位素偏移的精密量測

Precision Measurement of Hyperfine Intervals and Isotope Shift of D1 lines of Atomic Lithium

郭彥廷(Yen-Ting Kuo)

指導教授 ： 王立邦

國立清華大學/理學院/物理學系/碩士(2014年)

https://doi.org/10.6843/NTHU.2014.00057

摘要

我們使用交叉原子束法測量鋰原子6,7Li的D1譜線的超精細結構和同位素偏移。我們的光譜雷射是波長為670.9 nm的外腔式二極體雷射，並將雷射用Pound-Drever-Hall技術穩頻在Fabry-Perot干涉共振腔上，並且藉由改變共振腔腔長掃描鋰原子光譜。參考頻率雷射則是鎖在碘分子的譜線上。利用光電倍增管偵測雷射激發的原子螢光訊號，並記錄光譜雷射和參考雷射的拍頻做為訊號的頻率。

我們的實驗結果6,7Li在基態2S1/2的超精細結構分裂為228.198 (12) MHz和 803.495 (8) MHz，在第一激發態2P1/2超精細結構分裂為26.108 (9) MHz和 91.873 (5) MHz。而6,7Li 之間的同位素偏移為10533.800 (15) MHz。我們的量測釐清了不同團隊量測結果的爭議，並且與大部分的理論預測相符。

關鍵字

光譜 ； 鋰 ； 超精細結構

並列摘要

We have precisely measured the hyperfine intervals and isotope shift of D1 lines of atomic lithium 6,7Li in a collimated atomic beam. The spectroscopy laser, an external-cavity diode laser (ECDL) with wavelength 670.9 nm, which is locked to a Fabry-Perot cavity by Pound-Drever-Hall technique, scans the spectrums by changing the cavity length. The reference laser is locked to molecular iodine transition. The laser-induced fluorescence signal is detected by photomultiplier, and the beat frequency between spectroscopy laser and reference laser is recorded.

The results of 6,7Li for 2S1/2 hyperfine interval are 228.198 (12) MHz and 803.495(8) MHz. For 2P1/2 hyperfine interval, they are 26.108(9) MHz and 91.873(5) MHz. The isotope shift is 10533.800(15) MHz. Our results resolve the discrepancies between former measurements, and are consistent with most theoretical calculations.

並列關鍵字

spectroscopy ； lithium ； hyperfine structure

參考文獻

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