201525.fig.002a
(a)
201525.fig.002b
(b)
Figure 2: A plot of the variation of the singular orbital term 1 / 𝑟 2 (dotted-solid line) with the approximations of (a) [17, 18] (dash line), the conventional Greene-Aldrich of [19] (dash-dot line), and improved [23, 9698] (solid line) replacing the term 1 / 𝑟 2 with respect to 𝑟 , where 𝛿 = 0 . 1 f m 1 , and (b) the improved approximation [9698] with various shifting constants.