DFT analysis: Fe4 cluster and Fe (110) surface interaction studies with pyrrole, furan, thiophene and selenophene molecules.

DFT studies of both the Fe4 cluster and theFe(110) surface interaction with pyrrole, furan, thiophene,and selenophene showed that selenophene forms a stableradsorbate iron complex than the other heterocyclic molecules;this is consistent with the binding energy data thatwere calculated between the Fe cluster and the Fe(110)surface with the heterocycles. Furthermore, when theadsorption of the compounds with the iron cluster wasanalyzed by molecular orbital studies, the orbitals of selenopheneoverlapped more strongly with the Fe atom thanthat of the other molecules. In TD-DFT, the p ? p* peakobserved for the molecules disappeared when they formedcomplexes, and there appeared a charge transfer band(ligand to metal), thus confirming the coordination of thesemolecules with the cluster. The data suggest that thechemisorption is an exothermic process.