An essential singularity of the cotangent of the Coulomb-nuclear phase shift, and a finite limit of the nuclear part of the effective-range function derived at zero energy

Yu. V. Orlov

The Coulomb-nuclear phase shift ${\delta }_l^{(cs)}$, $\cot {\delta }_l^{(cs)}$ and a finite limit of the nuclear part ${\Delta }_l(k)$ of the effective-range function (ERF) are derived for an arbitrary or…