Critical size and surface effect of the hydrogen interaction of palladium clusters C. Nützenadel, A. Züttel, D. Chartouni, G. Schmid and L. Schlapbach Eur. Phys. J. D, 8 2 (2000) 245-250 Published online: 15 February 2000 DOI: 10.1007/s100530050033