EELS investigation of small gold clusters on mica substrates

Holst, Sabine; Legler, Werner

doi:10.1007/bf01426889

Cited by 6 publications

(6 citation statements)

References 13 publications

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“…The obtained equation (20) for surface damping constant is in a good agreement with the known size dependence of the electron-surface scattering rate R V F s / ) (γ , which was previously obtained for the dipole surface plasmon from various theoretical models and experimental data [6,29,[34][35][36][37][38] (and which can be in particular used to refine the value of correction coefficient K for various cluster materials). Note that the present dependence of the damping constant on multipole order ( l l s lm…”

Section: Surface and Volume Plasmons In A Spherical Nanoclustersupporting

confidence: 85%

“…In the simplest models (see, e.g., Refs. [12,13,29]), the electron loss spectra are calculated with no allowance for the possibility that the scattered electron may travel inside the cluster: the impact parameter is assumed to exceed the cluster radius in the most semiclassical calculations performed. In fact, this excludes the possibility of allowing for volume plasmons and does not allow one to compare the calculation results with the data of the experiments, in which clusters were bombarded with a thin electron beam at different impact parameters (including those being less than the radius) [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

“…In this work, the semiclassical model for inelastic scattering of fast electrons by a spherical cluster is developed and fits any values of the impact parameters both longer and shorter than the cluster radius. This model, as well as the above-mentioned works [11][12][13]29], is based on the use of quantum-mechanical correspondence between the frequency-and energy-dependent loss spectra of the electron decelerated at its classical (weakly perturbed) trajectory by the field of all plasmons it excites. Within the model used, the position, relative height, and width of the resonance peaks in the calculated loss spectra are determined, evidently, by the complex eigenfrequencies and excitation coefficients, which depend for every plasmon on its spatial structure (with electron velocity, impact parameter, and cluster radius given).…”

Section: Introductionmentioning

confidence: 99%

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Excitation of surface and volume plasmons in a metal nanosphere by fast electrons

2016

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Collective multipole oscillations (surface and volume plasmons) excited in a metal cluster by moving electron and corresponding inelastic scattering spectra are studied based on the hydrodynamic approach. Along with the bulk (dielectric) losses traditionally taken into account, the surface and radiative ones are also considered as the physical mechanisms responsible for the plasmon damping. The second and third mechanisms are found to be essential for the surface plasmons (at small or large cluster radii, respectively) and depend very differently on the multipole mode order. The differential equations are obtained which describe the temporal evolution of every particular mode as that one of a linear oscillator excited by the given external force, and the electron energy loss spectra are calculated. The changes in spectrum shape with the impact parameter and with the electron passage time are analyzed; the first of them are found to be in good enough agreement with the data of scanning transmission electron microscopy (STEM) experiments. It is shown that, in the general case, a pronounced contribution to the formation of the loss spectrum is given by the both surface and volume plasmons with low and high multipole indices. In particular, at long electron passage time, the integral (averaged over the impact parameter) loss spectrum which is calculated for the free-electron cluster model contains two main peaks: a broad peak from merging of many high-order multipole resonances of the surface plasmons and a narrower peak of nearly the same height from merged volume plasmons excited by the electrons that travel through the central region of the cluster. Comparatively complex dependences of the calculated excitation coefficients and damping constants of various plasmons on the order of the excited multipole result in wide diversity of possible types of the loss spectrum even for the same cluster material and should be taken into account in interpretation of corresponding electron energy loss spectroscopy (EELS) experiments.

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Section: Surface and Volume Plasmons In A Spherical Nanoclustersupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Excitation of surface and volume plasmons in a metal nanosphere by fast electrons

2016

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“…Since the bond between a single adatom and the surface is much weaker compared to that between different atoms, clusters will be formed on the surface mainly at defect sites. A similar (Volmer-Weber) growth mode has been observed for Au atoms evaporated on mica [23]. The number density of defects on mica depends on the actual history of the sample investigated but is expected to be similar to other cleaved dielectrics, i.e., of the order of 109 per cm 2 [9].…”

Section: Methodsmentioning

confidence: 66%

Kinetics of photo-induced dissociation of Na clusters deposited on Mica

Balzer¹,

Hartmann²,

Renger³

et al. 1993

Z Phys D - Atoms, Molecules and Clusters

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Abstract. Na clusters bound to mica surfaces have been irradiated with pulsed and cw visible laser light. Kinetic energy and angular distributions of the Na atoms desorbing from the clusters have been determined using cw two-photon laser-induced fluorescence detection. In addition the dependence of the desorption rate on laser power, wavelength and polarization has been measured. The most probable kinetic energy Eki n of the photodesorbed atoms at the surface temperature T s = 300 K was found to be Eki n = 18 + 5 meV, independent of taser irradiance (3~tJ/cm2...20mJ/cm 2) and wavelength (450nm, 505 rim, 658 urn). With increasing orientation angle between detection axis and surface normal (0°< O_< 90 °) Ekin was observed to decrease slightly, while it was nearly independent of surface temperature between Ts= 30 K and T s = 300 K. Also, with increasing radius of the Na clusters the desorbing Na atoms slowed down. The angular distribution of the Na atoms was of cos2-type with respect to the surface normal. These observations suggest that laser-induced desorption of Na from Na clusters bound to mica surfaces involves an initial rate-limiting step of direct surface plasmon excitation followed by a final step of delayed thermal desorption.

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“…In principle, EELS/ESI allows to study the transitions between the 2p, 3p, 4p, 3d and 4fvalence bands to the empty states above the Fermi level. For small particles, a number of papers have been devoted to EELS studies of plasmon excitations between 5 to 25 eV, which imply collective oscillations of the quasi-free electron gas [6,7]. The second category of useful information can be obtained by recording of the core edges which relate unambiguously to the presence of a given atom species.…”

Section: Introductionmentioning

confidence: 99%

High-resolution electron microscopy and electron energy-loss spectroscopy of giant palladium clusters

Oleshko

Volkov

Gijbels

et al. 1995

Z Phys D - Atoms, Molecules and Clusters

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Abstract. Combined structural and chemical characterization of cationic polynuclear palladium coordination compounds Pd561L60(OAc)180, where L = 1,10-phenantrotine or 2,2'-bipyridine has been carried out by highresolution electron microscopy (HREM) and analytical electron microscopy methods including electron energyloss spectroscopy (EELS), zero-loss electron spectroscopic imaging, and energy-dispersive X-ray spectroscopy (EDX). The cell structure of the cluster matter with almost completely uniform metal core size distributions centered around 2.3 _+ 0.5 nm was observed. Zero-loss energy filtering allowed to improve the image contrast and resolution. HREM images showed that most of the palladium clusters had a cubo-octahedral shape. Some of them had a distorted icosahedron structure exhibiting multiple twinning. The selected-area electron diffraction patterns confirmed the face centered cubic structure with lattice parameter close to that of metallic palladium. The energy-loss spectra of the populations of clusters contained several bands, which could be assigned to the delayed PdM~,s-edge at 362eV, the PdM3-edge at 533 eV and the Pd M2-edge at 561 eV, the N K-edge at about 400 eV, the O K-edge at 532 eV overlapping with the Pd Ma-edge and the carbon C K-edge at 284 eV. Background subtraction was applied to reveal the exact positions and fine structure of low intensity elemental peaks.

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EELS investigation of small gold clusters on mica substrates

Cited by 6 publications

References 13 publications

Excitation of surface and volume plasmons in a metal nanosphere by fast electrons

Excitation of surface and volume plasmons in a metal nanosphere by fast electrons

Kinetics of photo-induced dissociation of Na clusters deposited on Mica

High-resolution electron microscopy and electron energy-loss spectroscopy of giant palladium clusters

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