  The canonical function method (CFM) is a powerful means for solving the
Radial Schrodinger Equation. The mathematical difficulty of the RSE lies in the
fact it is a singular boundary value problem. The CFM turns it into a regular
initial value problem and allows the full determination of the spectrum of the
Schrodinger operator without calculating the eigenfunctions. Following the
parametrisation suggested by Klapisch and Green, Sellin and Zachor we develop a
CFM to optimise the potential parameters in order to reproduce the experimental
Quantum Defect results for various Rydberg series of He, Ne and Ar as evaluated
from Moore's data.
