where the 1 r term cancels the Coulomb term. The 1 r term may also be disregarded, yielding a slightly differently shaped potential. The finite potential approach leads to a significantly better agreement with experimental results for the hydrogen atom, and the same was later found by Gorecki et al. in a study of the confined molecular hydrogen ion. Besides using a step potential, also linear, harmonic and power series potentials have been used. If a power series potential of the form