Valence charges for ultrathin SiO2 films formed on Si(100) K. Hirose, M. Kihara, H. Okamoto, H. Nohira, E. Ikenaga, Y. Takata, K. Kobayashi and T. Hattori J. Phys. IV France, 132 (2006) 83-86 Published online: 11 March 2006 DOI: 10.1051/jp4:2006132016