On the feasibility of using ab initio calculations, both crystal orbital and molecular orbital, to predict XPS chemical shifts in fluorinated polyethylenes

Full crystal orbital calculations on polymers and model molecular orbital calculations on substituted butanes and pentanes, have been carried out to determine the core electron binding energies in fluorinated polyethylenes. The validity of using model compounds and the choice of basis set are critically discussed. Comparable calculations are reported for fluorine substituted methanes and compared with the experimental results. It is concluded that calculations on model compounds, that are more economic than full crystal orbital calculations, can only reproduce the broad trends and cannot give results in agreement with full polymer results.