Site-specific hydrogen reactivity and reverse charge transfer on Ge(111)-c(2×8)

Scanning tunneling microscopy (STM) and first-principleds pseudopotential calculations are used to show that the equilibrium binding site for hydrogen on Ge(111)-c(2×8) is the rest-atom site. Our calculations show the hydrogen-rest-atom configuration is 0.7 eV lower in energy than the hydrogen-adatom configuration. Reaction at the rest-atom site causes very local rest-atom to adatom reverse charge transfer, and this site-specific chemistry is imaged directly using STM measurements in combination with these calculations. © 1991 The American Physical Society.