MULTIPLE-SCATTERING ANALYSIS OF THE X-RAY ABSORPTION-SPECTRUM OF OS3(CO)12 CARBONYL CLUSTER

A new theoretical approach has been used to analyze the X-ray absorption cross section of Os3(CO)12 carbonyl cluster. The method is based on a direct fit of the experimental cross section which makes use of theoretical signals associated with relevant atomic configurations in the molecule. In the case of the Os-C = O arrangement, it has been found that the commonly employed multiple-scattering series converges slowly at low k values; the calculation has, therefore, been performed using a more efficient continued-fraction algorithm that provides the "exact" signal summed to all orders. An excellent agreement in the range k = 2.7-14.0 angstrom-1 has been obtained, basically using X-ray diffraction results.