An analysis was made of the Hopfield factor by using the linear muffin-tin orbital method. Based upon a uniform transferred charge density model, it was shown by calculation that the large difference in electronegativity between B and Mg favoured high l(l + 1) angular momentum hybridization and thus the Hopfield factor. The analysis was consistent with experimental results.

Electron-Phonon Coupling in Anion Metallic Solids and Superconducting MgB2. D.L.Yin, F.Yang, Z.Qi, R.S.Han: Chinese Physics Letters, 2002, 19, 1176-8