标题： 论原子物理中的电偶极子表示 显示英文标题

标题： On the Electric-Dipole Representation in Atomic Physics

摘要： 通过变分法显式地得到了在该变换定义中所理解的动量截断函数 f(k)。 我们给出了 f(k) 的表达式，该表达式用电子密度以及原子基态下电偶极矩的均方值来表示。 一个相关的结果涉及范德华相互作用，其远距离行为被证明与 R^{-8}成正比。 显示英文摘要

摘要： The unitary transformation that leads from the minimal-coupling description to the electric-dipole one is analysed in detail. The momentum cut-off function f(k), which is understood in the definition of such a transformation, is obtained explicitly by use of the variational method. We give an expression for f(k) in terms of the electron-density and of the mean-squared value of the electric-dipole moment of the atom in its ground state. A relevant consequence concerns the van der Waals interaction, whose long-distance behaviour turns out to be proportional to R^{-8} .