Adsorbate lone-pair-electron stimulated charge transfer between surface dangling bonds: methanol chemisorption on Si(1 1 1)-7 × 7

Unrestricted spin density functional theory in the flavor of B3LYP is used to explore the reaction pathways for CH3O–H dissociation over an adatom–rest atom pair site on Si(1 1 1)-7 × 7. We find that an adatom–rest atom pair site should be best regarded as a di-radical pair and that adsorbate lone-pair electrons stimulate efficiently the charge transfer from Si adatoms to Si rest atoms and vice versa. Our calculations show that rest atoms are more active than adatoms towards the dissociation of a lone-pair electron donor adsorbate.