Application of sum rules in the interpretation of electron energy loss spectra from transition metal oxides

In this paper, we model the linear dichroism of the L_2,3 absorption of Titanium in tetragonal symmetry as is relevant in the compound TiO₂. We develop a point charge model of the tetragonal potential, and use previous experimentally observed core level multiplet splittings to fix the values of the crystalline parameters necessary in the simulation. We then illustrate the use of the resultant difference spectra in determining ground state properties by application of a recently derived sum rule for the linear dichroism to obtain values of the electric quadrupole moment.