The moments S(mu) for -6 < or = mu < or = 2 and L(mu) for mu = 0, 1 and 2 are calculated for the helium sequence for atomic numbers Z up to 30 under a screened hydrogenic model. In this model, one describes the atom by single-particle hydrogenic wavefunctions and treats the initial and the final state as characterised by two different effective charge parameters Zi and Zf, respectively. An asymptotic expansion is made of the differential oscillator strength of the screened hydrogenic model. Assuming the value 287.6 for the coefficient of the term epsilon -7/2 for helium atom as given by Salpeter and Zaidi, the parameter Zf is determined for the helium sequence. This approach has resulted in values which are in reasonable agreement with the various moment values of other authors.

中文翻译：

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氦序列的偶极子振子强度分布矩。

在筛选的氢模型下，针对原子序数Z高达30的氦序列计算了-6 <或= mu <或= 2的矩S（mu）和mu = 0、1和2的矩L（mu）。在此模型中，人们通过单粒子氢波函数描述了原子，并分别用两个不同的有效电荷参数Zi和Zf表征了初始状态和最终状态。所筛选的氢模型的微分振荡器强度进行渐近扩展。假设由Salpeter和Zaidi给出的关于氦原子的项ε-7/2的系数的值为287.6，则为氦序列确定参数Zf。这种方法所产生的价值与其他作者的不同时刻价值是合理一致的。