Prediction of Double Dihydrogen Bonds at Two Semiconductor Surfaces

We present first-principles calculations for hydrogen peroxide adsorbed on the monohydrogenated {001} surfaces of silicon and germanium. These calculations reveal a preference for binding through one or two dihydrogen bonds─uncommon variants of traditional hydrogen bonds that have hitherto been almost absent from the surface science literature. Their presence here is confirmed through the identification of electronic and vibrational bonding signatures. Dihydrogen bonds on the silicon surface are found to be shorter and straighter than those on the germanium surface but not any stronger. Binding through a pair of dihydrogen bonds is more stable than through one, but by less than a factor of 2.