A MULTIPLE-SCATTERING EXAFS STUDY OF ORGANOMETALLIC COMPOUNDS - W(CO)(6) AND THYLBENZENE)W(CO)(3)(1,3,5-TRIMETHYLBENZENE)W(CO)3

Multiple scattering effects in EXAFS of two organometallic compounds, W(CO)(6) and (1,3,5-trimethylbenzene) W(CO)(3), at the tungsten L(III) edge are analyzed. The multiple scattering contributions are calculat ed by using a magnetic quantum number expansion, which is efficient an d exact. For both molecules forward scattering effects in the almost l inear metal-carbonyl chains play a dominant role. In the case of W(CO) (6) the octahedral symmetry gives rise to additional higher-order mult iple scattering effects. Structural parameters are determined by nonli near least square refinement. The hence determined tungsten-carbon and tungsten-oxygen distances in W(CO)(6) are 2.05 Angstrom and 3.19 Angs trom, respectively. The method gives interatomic distances with an acc uracy of similar to 0.02 Angstrom.