Properties of small TiO2, ZrO2 and HfO2 nanoparticles S. M. Woodley, S. Hamad, J. A. Mejías and C. R. A. Catlow J. Mater. Chem., 2006,16, 1927-1933 DOI: 10.1039/B600662K http://pubs.rsc.org/en/content/articlelanding/2006/JM/b600662k Thank you very much.