Check out Yinan’s communication in J. Chem. Phys. demonstrating that conical intersections in models of defects at the silicon-silicon oxide interface facilitate ultrafast non-radiative decay. Decay via such conical intersections may play a role in determining the photoluminescence spectrum of oxidized silicon nanoparticles.
Also, don’t forget to take a look at his recent J. Chem. Phys. article on preventing symmetry breaking in multireference wavefunctions.