Comparison of three numerical techniques for calculating eigenvalues of an unsymmetrical double minimum oscillator

Disagreement between calculated vibrational eigenvalues for the E, F 1Σ+g state of H2 obtained by three different numerical techniques has been interpreted in the literature in terms of inherent inadequacies of these techniques. We have tested these three numerical procedures by using each to obtain the eigenvalues of an unsymmetrical double minimum potential. An analytical potential was used to eliminate uncertainties introduced by interpolation. All three techniques are shown to give accurate results when properly applied.