TY - JOUR T1 - Transition from nanoparticle to molecular behavior: a femtosecond transient absorption study of a size-selected 28 atom gold cluster JF - Chemical Physics Letters Y1 - 2002 A1 - Link, Stephan A1 - El-Sayed, Mostafa A A1 - Schaaff, T. G. A1 - Whetten, R. L. AB - The ultrafast electron dynamics of chemically prepared gold nanoclusters with a 28 atom gold core surrounded by 16 glutathione molecules were investigated. After excitation with femtosecond laser pulses these clusters show an induced transient absorption in the visible from 2.58 to 1.65 eV (480-750 nm) with a maximum around 2.07 eV (600 nm). The excited state relaxation shows a biexponential decay with a subpicosecond and a longer nanosecond decay time independent of the laser pump power. These results are different from those observed previously for larger gold nanoparticles, which suggests that the Au-28-glutathione system shows molecular properties. (C) 2002 Elsevier Science B.V. All rights reserved. VL - 356 SN - 0009-2614 N1 - Link, S El-Sayed, MA Schaaff, TG Whetten, RL M3 - 10.1016/s0009-2614(02)00306-8 ER -