Vibronic mass computation for the <i>EF</i>–<i>GK</i>–<i>H</i> ¹Σ_g⁺ manifold of molecular hydrogen

A variational procedure is described for the computation of the non-adiabatic mass-correction matrix applicable for multi-dimensional electronic manifolds. The 30-year-old computations of Wolniewicz, Dressler, and their co-workers are appended with the computed vibronic mass-correction functions corresponding to the <i>EF</i>–<i>GK</i>–<i>HH¯</i>–<i>S5</i>–<i>S6</i> 1Σg+ manifold of the hydrogen molecule. Initial results are reported for the vibronic energies. Necessary further improvements and further developments are discussed.