TY - JOUR AU - Lawler, H AU - Rehr, J AU - Vila, F AU - Dalosto, SD AU - Shirley, Eric AU - Levine, Zachary C2 - Physical Review B (Condensed Matter and Materials Physics) DA - 2008-01-01 00:01:00 LA - en PB - Physical Review B (Condensed Matter and Materials Physics) PY - 2008 TI - Optical to UV spectra and birefringence of SiO2 and TiO2:  first-principles calculations with excitonic effects ER -