Relationships between the parameters of quantum-defect theory
A. R. P. Rau · Physical Review A · 1988
In the general form of quantum-defect theory, the basis functions of the long-range potential are parametrized in terms of six real functions of energy and angular momentum. The parameters above and below zero energy are shown to be connected through simple relationships upon analytic continuation. These relationships are completely general, valid for any long-range field, and are expressions of the analyticity properties of the underlying Jost functions.