Harris-Method Calculations of Electron and Positron Scattering by Hydrogen-Like Ions

The Harris method with 50-term and 56-term Schwartz-type-like correlated trial functions is applied to the s -wave elastic electron and positron scattering, respectively, by the hydrogen like ions He + , Li ++ , Be 3+ and B 4+ . These systems are difficult to treat by the Kohn or the Hulthén method. However, the matrix elements necessary in the Harris method can be obtained without numerical integration of the coulomb wave functions. In the case of the e+He + scattering, the results are compared with those of other previous calculations.