Theoretical Analysis of Fe K-Edge XANES on Iron Pentacarbonyl.

ABSTRACT: Iron pentacarbonyl (Fe(CO)5) is a versatile material that is utilized as an inhibitor of flame, shows soot suppressibility, and is used as a precursor for focused electron-beam-induced deposition (FEBID). X-ray absorption near-edge structure (XANES) of the K edge, which is a powerful technique for monitoring the oxidation states and coordination environment of metal sites, can be used to gain insight into Fe(CO)5-related reaction mechanisms in in situ experiments. We use a finite difference method (FDM) and molecular-orbital-based time-dependent density functional theory (TDDFT) calculations to clarify the Fe K-edge XANES features of Fe(CO)5. The two pre-edge peaks P1 and P2 are mainly the Fe(1s) ? Fe-C(?*) and Fe(1s) ? Fe-C(?*) transitions, respectively. When the geometry transformed from D 3h to C 4v symmetry, a ?30% decrease of the pre-edge P2 intensity was observed in the simulated spectra. This implies that the ? bonding of Fe and CO is sensitive to changes in geometry. The following rising edge and white line regions are assigned to the Fe(1s) ? Fe(4p)(mixing C(2p)) transitions. Our results may provide useful information to interpret XANES spectra variations of in situ reactions of metal-CO or similar compounds with ? acceptor ligandlike metal-CN complexes.

SUBMITTER: Chen WT 

PROVIDER: S-EPMC7081404 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature