Atomic and Electronic Structure of Pyrrole on Ge(100)

Abstract

We have performed ab initio pseudopotential density-functional calculations for pyrrole adsorbed on the Ge(100) surface in order to investigate its atomic and electronic structure. A large number of the pyrrole/Ge(100) adsorption configurations that could result from cycloadditions and Lewis acid−base reactions were examined. The configuration with both Ge−N and Ge−C linkages was found to be the most stable. The Ge−N linkage is formed by dative bonding after N−H dissociation, and the Ge−C linkage is a weak chemical interaction leading to the loss of aromaticity from the pyrrole ring. The pyrrole molecule bridges two down-Ge atoms in adjacent Ge dimer rows. This configuration was used to explain the experimental scanning tunneling microscopy (STM) images.