The motivation for this theoretical study is the interpretation of experimental X-ray absorption data for Ti-containing amorphous materials designed and synthesized by the University of Tennessee group of Barnes3. The spectra display systematic shifts of the ionization edge and pre-edge features with increasing coordination of titanium by chloride. Four sets of compounds of increasing size have been studied to explore convergence of the finite-cluster calculations. Three sets are Ti(OH)nCl4-n, Ti(OSiH3)nCl4-n, and Ti[OSi(OSiH3)3]nCl4-n, for n=0,1,2,3,4. The fourth set is composed of yet larger systems formed from the actual cubic building blocks used to construct the catalyst3. Hartree-Fock, and density functional theory within the local density approximation and also with the B3LYP functional are compared with time-dependent density functional theory from the core-hole state and experimental data.This research was conducted as part of the Chemistry Endstation project with funding from the Office of Advanced Scientific Computing research, the Department of Energy under contract to the University of Tennessee, and was performed in part using resources of the National Center for Computational Sciences at Oak Ridge National Laboratory under contract DE-AC05-00OR22725.3 Synthesis and structure of functional spherosilicate building blocks for materials synthesis, C. E. Barnes et. al, Journal of Organometallic Chemistry, 691, 3213-3222, 2006.

Density functional study of the X-ray absorption spectra of titanium catalysts

239th National Meeting (2010)

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