The colours of nanometric gold - Optical response functions of selected gold-cluster thiolates R. B. Wyrwas, M. M. Alvarez, J. T. Khoury, R. C. Price, T. G. Schaaff and R. L. Whetten Eur. Phys. J. D, 43 1-3 (2007) 91-95 Published online: 24 May 2007 DOI: 10.1140/epjd/e2007-00117-6