Limits on an Electromagnetic Fifth Force

In analogy to the proposed gravitational "fifth" force, limits can be set on the range $\lambda$ and the strength $\beta$ of an electrical fifth force. Specifically we consider the potential $V=\frac{(e^2}{r)}(1+{\beta e}^{-r\lambda })$ and show that there is a region near $\lambda =1\mathrm{}$ μm where existing experiments set relatively poor limits on $\beta$.