Computational Materials Science Network Team on ''Excited states and response functions''

This report covers the final one-year period of work done by the Principal Investigator (S. T. Pantelides) and his group in collaboration with other team members. The focus of the work was to pursue understanding of core excitation spectra in doped manganites where experimental data obtained at Oak Ridge National Laboratory by S. J. Pennycook showed inequivalent Mn atoms. Calculations found that doping sets up a Peierls-like instability that drives the observed distortion. Further calculations of electron-energy-loss spectra to account for the observed L23 ratios in the Mn L2,3 spectra will be pursued in the future