Atoms in crossed fields: calculations for barium and hydrogen
Atoms in crossed fields: calculations for barium and hydrogen
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DOI：
10.1088/0953-4075/30/16/004
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发表时间：
1997-08
期刊：
影响因子：
--
通讯作者：
J. Rao;K. Taylor
中科院分区：
文献类型：
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作者：
J. Rao;K. Taylor
Halley等人以前开发的用于实验室强度静电场和磁场中的非氢原子的方法（分开处理，并且在平行几何组合中）已经扩展到也处理交叉场。受伦敦帝国理工学院Connerade等人最近实验结果的启发，我们用这种方法计算了这些实验中测得的交叉场和钡的光吸收谱。计算结果与实验结果吻合良好。此外，计算补充实验已允许实验磁场强度被确定为优于0.3%和钡场自由量子缺陷被确定为优于0.01%（模单位）。相应的光吸收光谱也已计算氢。比较计算的光谱和波函数的两个原子已确定的非氢行为的钡，特别是在较长的波长，是由于异常的光谱位置，在近零电场，少数的“种子”状态。这些“种子”状态保持在它们的异常位置，但随着电场强度的增加，振荡器强度增加，从而产生显著的、局部的、非类氢光吸收特征。对于逐渐变短的波长，我们到达一个点，在那里“种子”状态不再可以识别，和一个更均匀分布的振荡器强度的频谱结果。
A method previously developed by Halley et al for non-hydrogenic atoms in laboratory strength static electric and magnetic fields (treated separately, and in a parallel geometry combination) has been extended to also handle crossed fields. Stimulated by results from recent experiments by Connerade et al at Imperial College, London, we have used the method to calculate the crossed field and barium photoabsorption spectra measured in these experiments. The calculated results are found to be in excellent agreement with those from experiment. Moreover, calculation complementing experiment has allowed the experimental magnetic field strength to be identified to better than 0.3% and barium field-free quantum defects to be determined to better than 0.01% (modulo unity). The corresponding photoabsorption spectra have also been calculated for hydrogen. Comparing calculated spectra and wavefunctions for the two atoms has identified the non-hydrogenic behaviour of barium, especially at longer wavelengths, to be due to the anomalous spectral locations, at near-zero electric field, of a small number of `seed' states. These `seed' states remain in their anomalous locations but grow in oscillator strength as the electric field strength is increased, thus giving rise to significant, localized, non-hydrogenic photoabsorption features. For progressively shorter wavelengths we reach a point where `seed' states can no longer be identified, and a much more uniform distribution of oscillator strength in the spectrum results.