The jellium model of simple metal clusters has enjoyed remarkable empirical success, leading to many theoretical questions. In this review, we first survey the hierarchy of theoretical approximations leading to the model. We then describe the jellium model in detail, including various extensions. One important and useful approximation is the local-density approximation to exchange and correlation effects, which greatly simplifies self-consistent calculations of the electronic structure. Another valuable tool is the semiclassical approximation to the single-particle density matrix, which gives a theoretical framework to connect the properties of large clusters with the bulk and macroscopic surface properties. The physical properties discussed in this review are the ground-state binding energies, the ionization potentials, and the dipole polarizabilities. We also treat the collective electronic excitations from the point of view of the cluster response, including some useful sum rules.

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The physics of simple metal clusters: self-consistent jellium model and semiclassical approaches

Ultraviolet photoelectron spectra (UPS) were recorded for mass‐selected negative clusters of copper (1–411 atoms), silver (1–60 atoms), and gold (1–233 atoms), using photodetachment lasers at 6.4 and 7.9 eV photon energy. The results provide a direct estimate of the vertical electron affinity (EA) of these clusters and information on the evolution of the d bands of copper and gold as a function of cluster size. The large even/odd alternation of EA in small clusters of these metals in earlier work is found to largely disappear as the cluster size exceeds 40 atoms. The ellipsoidal shell model is shown to be consistent with the observed EA behavior of all three metals, the predicted spherical shell closing at cluster 58 being evident for silver and gold. The UPS data show a smooth evolution of the d band toward that of the bulk metal.

Ultraviolet photoelectron spectra of coinage metal clusters

Ultrasound mediated delivery of drugs and genes to solid tumors.

Background— Prognosis of ischemic cardiomyopathy still remains poor because of the lack of effective treatments. To develop a noninvasive therapy for the disorder, we examined the in vitro and vivo effects of extracorporeal shock wave (SW) that could enhance angiogenesis. Methods and Results— SW treatment applied to cultured human umbilical vein endothelial cells significantly upregulated mRNA expression of vascular endothelial growth factor and its receptor Flt-1 in vitro. A porcine model of chronic myocardial ischemia was made by placing an ameroid constrictor at the proximal segment of the left circumflex coronary artery, which gradually induced a total occlusion of the artery with sustained myocardial dysfunction but without myocardial infarction in 4 weeks. Thereafter, extracorporeal SW therapy to the ischemic myocardial region (200 shots/spot for 9 spots at 0.09 mJ/mm2) was performed (n=8), which induced a complete recovery of left ventricular ejection fraction (51±2% to 62±2%), wall thickening frac...

Extracorporeal Cardiac Shock Wave Therapy Markedly Ameliorates Ischemia-Induced Myocardial Dysfunction in Pigs in Vivo

The electronic metal-support interaction (EMSI), which acts as a bridge between theoretical electronic study and the design of heterogenous catalysts, has attracted much attention. Utilizing the interaction between the metal and the support is one of the most essential strategies to enhance electrocatalytic efficiency due to structural and synergetic promotion. To date, as the ideal model for realizing EMSI, many types of single-atom catalysts (SACs) have been developed. The understanding of the electronic interaction on SACs has also been pushed to a higher level. However, systematic theories and operando experiments are seldom reported, and will be necessary to put forward and be carried out, respectively. Herein, the types, characterization, mechanism, and electrocatalytic applications of EMSI are comprehensively summarized and discussed. In addition to the basic information above, the challenges, opportunities, and future development of the EMSI on SACs are also proposed to present an overall view and reference to the later research.

Electronic Metal–Support Interaction of Single-Atom Catalysts and Applications in Electrocatalysis

Experimental ionization potentials (I) and electron affinities (A) of metal clusters MeN are compiled for a variety of systems and their size dependence is analyzed. In the theoretical part, we perform semiclassical density variational calculations using the spherical jellium model and the local density approximation. For alkali systems and, to some extent, also for some nonalkali systems, the calculated values of I and A reproduce very well the average size dependence of the measured quantities, if their common bulk limit W is adjusted to the experimental bulk work function. This holds even for rather small systems where I and A are no longer linear in N−1/3. We discuss the extent to which classical models for the energetics of charged metal spheres can account for the correct size dependence in the large‐cluster limit. We point out that the deviation of the slope parameters α and β in the asymptotic expressions I∼W+α(e2/rs)N−1/3, A∼W−β(e2/rs)N−1/3 from the values (1)/(2) , which depends on the material ...

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Finite-size effects in ionization potentials and electron affinities of metal clusters

Induction of stress fibres and intercellular gaps in human vascular endothelium by shock-waves.

For more than a decade, extracorporal shock wave lithotripsy has been a standard clinical method for the treatment of urinary stones. However, side effects that are likely to be correlated to vessel damage can often be observed using noninvasive diagnostic techniques, e.g., magnetic resonance imaging. To avoid side effects it is useful to understand the interaction between shock waves and the vascular system. In particular, this is important in view of new applications like gallstone lithothripsy. In the present study, we exposed human umbilical vessels to electromagnetically generated ultrasound shock waves to analyze subsequent alterations of their endothelial layer. Following en face preparation and fluorescent staining, the endothelium was examined in a confocal laser scanning microscope. Endothelial cells of the shock wave exposed vessels revealed permeabilization of plasma membranes and mitochondrial alterations as potentially lethal damage. An increase in the number of stress fibres may indicate functional changes possibly influencing vessel wall permeability.

Shock wave induced endothelial damage - in situ analysis by confocal laser scanning microscopy

We report on semiclassical density variational calculations for spherical alkali metal clusters in the jellium model. We derive liquid-drop model expansions for total energy, ionisation potential and electron affinity and test the coefficients numerically for clusters with up toN=105 atoms. From the limitN→∞, we obtain excellent agreement with surface tensions and work functions evaluated for an infinite plane metal surface.

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Semiclassical variational calculation of liquid-drop model coefficients for metal clusters

In vivo and in vitro experiments show that high energy shock waves (HESW) lead to transient decrease of tumour volumes and a transient reduction of tumour cell proliferation. Combining HESW with cytostatic drugs or cytokines leads to a pronounced enhancement of anti-tumour effects. We investigated the time courses of the effects of HESW on cell membranes and mitochondria. Both membrane permeabilisation and mitochondrial alterations due to HESW treatment occur as transient effects and can be regenerated on a long term scale.

M. Seidl

Papers

Finite-size effects in ionization potentials and electron affinities of metal clusters

Induction of stress fibres and intercellular gaps in human vascular endothelium by shock-waves.

Shock wave induced endothelial damage - in situ analysis by confocal laser scanning microscopy

Semiclassical variational calculation of liquid-drop model coefficients for metal clusters

The Effects of High Energy Shock Waves on Cell Membranes and Mitochondria