The extreme-ultraviolet emission line (424 Å) of the intercombination 1s ²2s ^{2 1} S ₀–1s ²2s2p ³ P ₁ transition of Ar xv can potentially characterize the electron temperature of astrophysical plasma. Various theoretical studies have investigated the intercombination transition rate, which is essential for the plasma diagnostics; however, experimental difficulties have prevented its measurement. We present here measurement of the lifetime of the ³ P ₁ excited state of Ar xv, providing the experimental value of the intercombination transition rate. Employing time-resolved plasma-assisted laser spectroscopy, a method we recently demonstrated, enables us to measure this submicrosecond lifetime. The experimental result exhibits a 25%–43% higher transition rate than theoretical predictions.

中文翻译：

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时间分辨激光光谱法测量 Ar xv 日冕组合线的实验室跃迁率


Ar xv 互组合 1s ² 2s ^{2 1} S ₀ –1s ² 2s2p ³ P ₁跃迁的极紫外发射线 (424 Å) 可以潜在地表征天体物理等离子体的电子温度。各种理论研究已经研究了组合转变率，这对于等离子体诊断至关重要；然而，实验困难阻碍了它的测量。我们在这里测量了 Ar xv 的³ P ₁激发态的寿命，提供了组合跃迁率的实验值。采用我们最近演示的时间分辨等离子体辅助激光光谱法，使我们能够测量这种亚微秒寿命。实验结果显示转换率比理论预测高 25%–43%。