@article {1197,
	title = {Transition from nanoparticle to molecular behavior: a femtosecond transient absorption study of a size-selected 28 atom gold cluster},
	journal = {Chemical Physics Letters},
	volume = {356},
	number = {3-4},
	year = {2002},
	note = {Link, S El-Sayed, MA Schaaff, TG Whetten, RL},
	month = {Apr},
	pages = {240-246},
	abstract = {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.},
	isbn = {0009-2614},
	doi = {10.1016/s0009-2614(02)00306-8},
	author = {Link, Stephan and El-Sayed, Mostafa A and Schaaff, T. G. and Whetten, R. L.}
}
@article {1199,
	title = {Visible to infrared luminescence from a 28-atom gold cluster},
	journal = {Journal of Physical Chemistry B},
	volume = {106},
	number = {13},
	year = {2002},
	note = {Link, S Beeby, A FitzGerald, S El-Sayed, MA Schaaff, TG Whetten, RL},
	month = {Apr},
	pages = {3410-3415},
	abstract = {The luminescence properties of chemically prepared gold nanoclusters, each composed of a 28-atom core and a glutathione (GSH) adsorbate layer consisting of 16 molecules, were investigated. These clusters show a distinct absorption onset at 1.3 eV corresponding to the opening of an electronic gap within the conduction band (HOMO-LUMO gap). Here we report on the radiative properties of these molecular-like Bald clusters. By using a combination of different detectors with sensitivities in the visible to the infrared (2.0-0.8 eV), a broad luminescence extending over this entire spectral range was observed. Our results further suggest that the luminescence can be separated into two bands with maxima around 1.5 and 1.15 eV indicating that radiative recombination between the ground state and two distinctively different excited states takes place. The: origin of the observed luminescence bands is discussed using a solid state as well as a molecular model for the electronic structure and relaxation of the clusters. The total quantum yield of the luminescence: as measured at ambient temperature was approximated to be about (3.5 +/- 1.0) x 10(-3).},
	isbn = {1520-6106},
	doi = {10.1021/jp014259v},
	author = {Link, Stephan and Beeby, A. and FitzGerald, S. and El-Sayed, Mostafa A and Schaaff, T. G. and Whetten, R. L.}
}
@article {868,
	title = {Electron Dynamics of Passivated Gold Nanocrystals Probed by Subpicosecond Transient Absorption Spectroscopy},
	journal = {The Journal of Physical Chemistry B},
	volume = {101},
	year = {1997},
	note = {doi: 10.1021/jp962923f},
	month = {1997},
	pages = {3713 - 3719},
	publisher = {American Chemical Society},
	abstract = {The electronic dynamics of gold nanocrystals, passivated by a monolayer of alkylthiol(ate) groups, were studied by transient spectroscopy after excitation with subpicosecond laser pulses. Three solution-phase gold samples with average particle size of 1.9, 2.6, and 3.2 nm with size distribution less than 10\% were used. The photoexcitation in the intraband (surface plasmon region) leads to the heating of the conduction electron gas and its subsequent thermalization through electron?electron and electron?phonon interaction. The results are analyzed in terms of the contribution of the equilibrated ?hot? electrons to the surface plasmon resonance of gold. A different spectral response was observed for different sizes of gold nanoparticles. The results were compared to the dynamics of the large (30 nm diameter) gold nanocrystals colloidal solution. The size-dependent spectral changes are attributed to the reduction of the density of states for small nanoparticles. The observed variation in the kinetics of the cooling process in gold nanoparticles with changing the laser intensity is attributed to the temperature dependence of the heat capacity of the electron gas.The electronic dynamics of gold nanocrystals, passivated by a monolayer of alkylthiol(ate) groups, were studied by transient spectroscopy after excitation with subpicosecond laser pulses. Three solution-phase gold samples with average particle size of 1.9, 2.6, and 3.2 nm with size distribution less than 10\% were used. The photoexcitation in the intraband (surface plasmon region) leads to the heating of the conduction electron gas and its subsequent thermalization through electron?electron and electron?phonon interaction. The results are analyzed in terms of the contribution of the equilibrated ?hot? electrons to the surface plasmon resonance of gold. A different spectral response was observed for different sizes of gold nanoparticles. The results were compared to the dynamics of the large (30 nm diameter) gold nanocrystals colloidal solution. The size-dependent spectral changes are attributed to the reduction of the density of states for small nanoparticles. The observed variation in the kinetics of the cooling process in gold nanoparticles with changing the laser intensity is attributed to the temperature dependence of the heat capacity of the electron gas.},
	isbn = {1520-6106},
	url = {http://dx.doi.org/10.1021/jp962923f},
	author = {Logunov, Stephan L. and Ahmadi, Temer S. and El-Sayed, Mostafa A and Khoury, J. T. and Whetten, R. L.}
}
