The Ti-L2,3 edge spectra of rutile TiO2 have been calculated with the time-dependent density functional theory
(TDDFT), employing the zero-order regular approximation (ZORA) at both scalar relativistic and spin–orbit
coupling levels. The bulk rutile as well as its (110) surface has been considered with the aim of analyzing the
sensitivity of the calculated Ti L2,3 spectra to the different symmetry environments of the Ti atom in the two
conditions. A good agreement with the experiment has been obtained in both cases. The inclusion in the
theoretical scheme of both the configuration interaction and the spin–orbit coupling is essential to correctly
describe the intensity distribution among the L3- and L2-edge transitions. The fine structures of the spectra
reflect the symmetry environment of the absorbing Ti atom as well as the long range contribution from
neighbor Ti atoms.
